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The Aristean Calendar is a calendar reform proposed by Aristeo Canlas Fernando of Australia. It was devised in 1992.

It is almost identical to the Edwards perpetual calendar which has a 30:30:31 month length pattern instead of 31:30:30. It is just like the World Calendar except that the weeks begin on a Monday instead of a Sunday, and December 31 and June 31 of the former are the equivalent of the monthless and dateless Worldsday and Leapyear Day, respectively, of the latter. Christmas and Easter occur on different dates also. Year zero is the present 1 B.C. It is said to have the least variation against the Gregorian calendar as compared to other proposed solar calendars. [1]

The Aristean Calendar year layout by quarter
Quarter 1st month 2nd month 3rd month
01 02 03 04 05 06 07
08 09 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31
01 02 03 04
05 06 07 08 09 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30
01 02
03 04 05 06 07 08 09
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
01 02 03 04 05 06 07
08 09 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31
01 02 03 04
05 06 07 08 09 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30
01 02
03 04 05 06 07 08 09
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
Leap Year Day
01 02 03 04 05 06 07
08 09 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31
01 02 03 04
05 06 07 08 09 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30
01 02
03 04 05 06 07 08 09
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
01 02 03 04 05 06 07
08 09 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31
01 02 03 04
05 06 07 08 09 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30
01 02
03 04 05 06 07 08 09
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
World Peace Day

The Aristean calendar[]


Features of the Aristean calendar compared to the Gregorian calendar[]


  1. There are twelve months in a year—January to December.
  2. There are 365 days in a common year; 366 days in a leap year.
  3. A year is a leap year if it is divisible by four except if the century year is not divisible by 400.
  4. The year starts on January 1 and ends on December 31.
  5. The present year numbering is the same.
  6. The months with the same number of days are January, July, September, October, November and December.
  7. The day number during common years is the same from January 1 to February 28 and September 1 to December 31.
  8. The day number during leap years is the same from January 1 to February 29, May 1 to May 30, July 1 to July 31, and September 1 to December 31.


  1. To make the calendar uniform, the number of days in six of the months were changed. The new dates in the Aristean calendar are February 30, April 31 and June 31 which replace three dates in the Gregorian calendar--March 31, May 31 and August 31.
  2. A date and its day of the week are the same every year making the calendar perpetual.
  3. The months, quarters, and half-years are uniform and have a maximum difference of only one day, give or take. A month has either 30 or 31 days; a quarter has three months of either 91 or 92 days; and a half-year has six months of either 182 or 183 days.
  4. January 1 is fixed on Monday.
  5. The week has seven days except the last week of December, and on a leap year, the last week of June, when there are eight days.
  6. The week starts on Monday in conformance with the International Organization for Standardization (ISO) standard ISO 8601. Other ISO standards are simplified in the Aristean calendar.
  7. Each quarter has 31 days on the first month and 30 days each on the second and third months (31-30-30-day pattern). The quarter begins on Monday and ends on Sunday, except in the fourth quarter when it ends on World Peace Day, and during leap years, in the second quarter, on Leap Year Day.
  8. The first months of the quarters are January, April, July and October, and start on Monday.
  9. The second months of the quarters are February, May, August and November, and start on Thursday.
  10. The third months of the quarters are March, June, September and December, and start on Saturday.
  11. December 31 is the eighth day of the week. It is a no-weekday named as World Peace Day and is a public holiday throughout the world. For the religious, the day is the Grand Sabbath of the year.
  12. During Leap Years, June 31 is the eighth day of the week. It is a no-weekday simply named as Leap Year Day and is a bonus public holiday throughout the world. For the religious, it is the Glorious Sabbath.
  13. Christmas Day is on May 23, a Friday.
  14. Crucifixion Day, presently known as Good Friday, is fixed on August 17, a Saturday, or August 15, a Thursday if the day of the week when Jesus was actually crucified is followed.
  15. Resurrection Day, presently known as Easter, is fixed on August 21, a Wednesday, or August 19, a Monday if the day of the week when the tomb was found empty is followed.
  16. The 13th day of the month will never fall on a Friday.
  17. The year is not reckoned from the supposed birth of Jesus in 1 B.C. but from His crucifixion in that year.
  18. B.C. will not stand for Before Christ but Before Crucifixion. To distinguish the two, the latter will be abbreviated as BCA or Before Crucifixion in the Aristean calendar.
  19. A.D. will not stand for the Latin words anno Domini (in the year of Our Lord) but After Death. To distinguish the two, the latter will be abbreviated as ADA or After Death in the Aristean calendar.
  20. Year 0 is the present 1 B.C.; 1 BCA or -0001 (ISO) is the present 2 B.C.; 32 BCA or -0032 (ISO) is 33 B.C.; ADA 325 or +0325 (ISO) is A.D. 325; ADA 2007 or +2007 (ISO) is A.D. 2007.

Background and history[]

The Aristean calendar was inspired to Aristeo as “31-30-30, start on Monday” while he was driving to work one morning in January 1992. After researching in the local library and writing a manuscript about the calendar he devised based on the inspiration, Fairfield Advance, a local city newspaper published it on paper’s front page entitled “Time on his hands” [3] on 1992 November 3. Channel 9 TV, in its national evening news, presented it the following month on 1992 December 2. [4]

Initially, he named the calendar simply as “Perpetual Calendar”, then the Fernando Perpetual Calendar after his family name. Soon, however, Aristeo decided to lend his own name to the calendar. Coincidentally, his mother's name is "Gregoria" and her mother's name was "Julita", something that Aristeo saw as a parallel to the Gregorian calendar and its predecessor, the Julian Calendar. [5] Seeing, perhaps, a good sign, Aristeo modestly decided to bestow his first name to the "Aristean Perpetual Calendar", with hopes that it might succeed the Julian and Gregorian versions. Later still, Mr. Fernando realized the significance of the name Aristeo which is the Hispanic name of the Greek god Aristaeus. Aristaeus comes from the Greek word aristos (as in "aristocrat") meaning “best” or “number one”, suitable for calendar reform.

The Honorable Chris Haviland, MP for Aristeo’s electorate of Macarthur, presented the Perpetual Calendar at the Australian Federal Parliament on 1994 September 1 as recorded in House Hansard, page 949. [6]

The Honorable Michael Photios, MP, New South Wales State Minister for Multicultural and Ethnic Affairs, on 1994 December 12, expressed his approval of the calendar proposal which he “certainly think has merit.” He said that it “is a simple enough rationalization of the way we view our time and is one worthy of consideration.” What he found “particularly attractive is that calendars and diaries would not have to be reprinted every year. Around the world this represents a lot of trees and saved paper, and makes the greatest sense environmentally.” [7]

When His Holiness, Pope John Paul II, visited Australia in 1995 January, Aristeo requested an audience with him to present the calendar idea. Susan Winkworth, Executive Assistant of the Papal Visit, said that due to the Pope’s brief visit, Vatican protocols, and his health, “private audiences have not been permitted.” She, however, commented that the calendar proposal “is well-devised, logical, simple to follow and also environmentally considerate.” [8]

Dr Richard Brittain, Secretary, National Time Committee of the National Standards Commission (of Australia) furnished Aristeo a copy of the Commission’s Information Leaflet No. 28 on Calendars issued in 1995 April. It mentioned the Fernando Perpetual Calendar from Australia as “one of the most recently suggested forms of perpetual calendars” which claims the following advantages: “(a) there are no ‘monthless’ or ‘dateless’ days; (b) it affects less days in the current Gregorian calendar than any other proposed perpetual calendar; and (c) there are no Fridays on the 13th.” [9]

The Aristean calendar was presented to the Sydney Organizing Committee for the Olympic Games (SOCOG) as a proposal to proclaim it during the closing ceremony of the 2000 Olympic Games. It explored this possibility but eventually set it aside when the Australian government failed to present it to the United Nations because of its religious significance or meaning. The Games is supposed to be non-sectarian and could have caused controversy to the “best Games ever” if it did so. [10]

The Lord Mayor of Sydney, Councilor Frank Sartor, a member of SOCOG, wrote to the Vice Chancellor of the University of Sydney, Professor Don McNicol, “asking for his views on the best way to progress the calendar proposal” in 1994 November. [11]

In response, on 1995 February 2, Professor Paul Crittenden, Dean, Faculty of Arts, The University of Sydney, after discussing the proposal with a number of colleagues, mainly mathematicians, wrote a fair assessment of the idea. He said that “the proposal works in a technical sense and could have some advantages, but the whole world would have to agree on it and it would need to be introduced simultaneously.” His suggestion was “to try to get it adopted by the United Nations in the first place.” He further commented that Aristeo’s “ingenuity in devising the calendar is linked with idealism and a very worthy concern for world peace and understanding.” [12]

The Lord Mayor then wrote to the Chief, Planning and Special Programmes Section of the United Nations, “to direct the calendar proposal to an appropriate branch or forum for considered attention” in 1995 February. The Section’s new chief, Ms Susan Markham, suggested in 1996 August that the government of Australia should raise the calendar reform matter in the appropriate forum, such as the United Nations’ Economic and Social Council (ECOSOC). [13]

In 1996, the Honorable John Fahey, MP, who succeeded Chris Haviland, wrote that “the Perpetual Calendar sounds like a very interesting and useful idea. I imagine that some religious groups would object on the basis of a seven day week and other particular religious references, but it seems to me that your concept deserves greater discussion.” [14] Failing to get the Australian government to present the calendar reform matter at the United Nations, Aristeo proclaimed the Aristean calendar as the official primary standard calendar of the world on 2000 December 31. [15] It replaces the Gregorian calendar as the de facto calendar for civil usage regardless of religious affiliation. For Christians, however, dates have been fixed to observe holy days on their correct dates.

In 2003, Aristeo was able to prove to his own satisfaction that Jesus Christ was crucified on 1 B.C. August 17 after a four-year study. [16] In 2006, he was able to prove that Jesus was born on 33 B.C. May 23. [17] Both dates were revelations that he first heard in 1983. They may have been waiting to be proven first before the calendar could be implemented.

Benefits of the Aristean calendar[]

  1. The Aristean calendar and the Gregorian calendar are similar. The former is simpler, more uniform and easier to remember than the later. Hence, changeover will not be drastic.
  2. The Aristean calendar has a constant day-date relationship making it perpetually the same every year. One can even memorize it and is valid on any year. For example: January 1 will always be a Monday; December 25, always Tuesday. The first Wednesday of September will always fall on September 5; Thanksgiving Day which is the fourth Thursday of November always falls on November 22.
  3. The divisions of months, quarters and half-years in the Aristean are more uniform and have lesser differences than in the Gregorian. It has only either 30 or 31 days in a month, 91 or 92 days in a quarter, and 182 or 183 days in a half-year. In the economic sphere, this is favorable and expedient.
  4. To the superstitious, the 13th will NEVER fall on a Friday.
  5. Unsold calendars and diaries will not be discarded anymore. They can be sold anytime of the year and the years after. Losses and wastage are eliminated.
  6. Calendars will not have to be printed every year saving many trees.
  7. Holidays can easily be planned well in advance avoiding unscheduled absences.
  8. Activities and special occasions regularly held every year would become easier to schedule and remember. There is no need to reinvent the schedule year after year. For example, school terms and holidays, festivals, public holidays, daylight saving dates, birthdays, anniversaries, taxation dates, Wimbledon and the US Open in tennis.
  9. The week starts on Monday making it compatible with the format of the plain and common standard ISO 8601.
  10. ISO ruling on week dates is simplified by fixing them. For example, week 1 is from January 1-7; week 28, from July 8-14; week 52, from December 24-31 every year.
  11. The movable observance of Good Friday in the Gregorian calendar is fixed on August 17, a Saturday, or on August 15, a Thursday, if the day of the week when Jesus was actually crucified is followed. It is named Crucifixion Day.
  12. The movable feast of Easter in the Gregorian calendar is fixed on August 21, a Wednesday, or on August 19, a Monday, if the day of the week when Jesus actually resurrected is followed. It is named Resurrection Day.
  13. Christmas Day is celebrated on May 23. This settles the controversy on when to celebrate the birth of Jesus.
  14. There are several fixed long weekends. These are from May 22, Thursday, to May 25, Sunday (Christmas week, 4 days); June 29, Saturday to June 31, Leap Year Day (during leap years, 3 days); August 15, Thursday, to August 19, Monday (Holy Week based on actual day of the week, 5 days) or August 17, Saturday, to August 21, Wednesday (Holy Week based on actual date); December 29, Saturday to January 1, Monday (World Peace Day-New Year’s Day, 4 days)

ISO 8601 and the Aristean calendar[]


The epoch or year zero of the Aristean calendar is the present 1 B.C. However, the year is not reckoned anymore from the birth of Jesus but from His crucifixion and death in 1 B.C. The ISO year numbering after 1 B.C. remains the same.

The Aristean calendar is compatible with ISO 8601, especially in the designation day of the week from Monday to Sunday which is Day 1 to Day 7.

The Calendar year consists of four digits and is written in the format


where [YYYY] is the year with century.

The Calendar date is written in the format



where [YYYY] is the year with century, [MM] is the month of the year from 01 to 12, and [DD] is the day of the month from 01 to 31.

The Calendar week date is simplified in the Aristean calendar by designating specific dates to week number. For example, Week 1 will be from January 1 to 7, Week 28 from July 8 to 14, Week 52 from December 24 to 31. It is written in the format:



where [YYYY] is the year with century, [W] is the prefix of the week number [ww] from 01 to 52, and [D] is the single-digit day number from 1 to 7 equivalent to Monday to Sunday. Day 8 is used only for June 31, Leap Year Day, and December 31, World Peace Day. ISO 8601 ruling has to be amended to accommodate this eighth day of the week.


Week Number Inclusive Dates Week Number Inclusive Dates
01 January 1-7 27 July 1-7
02 January 8-14 28 July 8-14
03 January 15-21 29 July 15-21
04 January 22-28 30 July 22-28
05 January 29-February 4 31 July 29-August 4
06 February 5-11 32 August 5-11
07 February 12-18 33 August 12-18
08 February 19-25 34 August 19-25
09 February 26-March 2 35 August 26-September 2
10 March 3-9 36 September 3-9
11 March 10-16 37 September 10-16
12 March 17-23 38 September 17-23
13 March 24-30 39 September 24-30
14 April 1-7 40 October 1-7
15 April 8-14 41 October 8-14
16 April 15-21 42 October 15-21
17 April 22-28 43 October 22-28
18 April 29-May 4 44 October 29-November 4
19 May 5-11 45 November 5-11
20 May 12-18 46 November 12-18
21 May 19-25 47 November 19-25
22 May 26-June 2 48 November 26-December 2
23 Jun 3-9 49 December 3-9
24 June 10-16 50 December 10-16
25 June 17-23 51 December 17-23
26 June 24-31 52 December 24-31


2007 July 24 is written as 2007-W30 or 2007W30 or 2007-W30-3 or 2007W303

2008 May 15 is written as 2008-W20 or 2008W20 or 2008-W20-4 or 2008W204

The Calendar ordinal date is written in the format


where [YYYY] is the year with century, and [DDD] is the day number of the date from January 1, from 001 to 365 during common year and from 001 to 366 during leap year. The day number [19] in the Aristean calendar of January 25 is Day 25; May 23 is Day 145; August 17 is Day 230 and in a Leap Year, it is Day 231. So 2007 August 17 is written as 2007-230 or 2007230.

Day number 001 to 182 are the same during common year and leap year. During leap years, the day number of a date after June 30 is 1 more than during common year. Dividing the day number by 7 can help determine the day of the week of the date and its week number. During leap years, subtract 1 from the day number if it is more than 182 before dividing. The remainder determines the day of the week while the whole number plus 1 determines the week number.

Determination of the day of the week[]


To determine the day of the week of any date of any year is easy in the Aristean calendar by following these simple steps:

  1. Determine in which month of the quarter the date belongs to, i.e. 1, 2, or 3.
  2. Add the constant to the date to get the sum, i.e. 0 for the first month, 3 for the second month, and 5 for the third month. Note that the constant is the number of blank spaces before the first day of the month in question in the calendar.
  3. Divide the sum by 7 and find the remainder. The remainder determines the day of the week, i.e. 1 is Monday; 2, Tuesday; 3, Wednesday; 4, Thursday; 5, Friday; 6, Saturday; 0, Sunday.
Month number in the quarter 1 2 3
Maximum number of days in month* 31 30 30
First Quarter January February March
Second Quarter April May June
Third Quarter July August September
Fourth Quarter October November December
Constant to be added to the date 0 3 5

  • Exceptions are December 31 which is World Peace Day or Grand Sabbath, and June 31 which is Leap Year Day or Glorious Sabbath. Both these dates do not have the regular name day of the week.


  1. April 15 – April is the first month of the quarter, hence 0 is added to 15 to give a total of 15. 15 is divided by 7 gives 2 remainder 1. Hence, April 15 is Monday.
  2. August 22 – August is the second month of the quarter, so 3 is added to 22 giving a total of 25. Divided 25 by 7. The answer is 3, remainder 4. Hence, August 22 is Thursday.
  3. June 9 – June is the third month of the quarter. Add 5 to 9 giving 14. Divide 14 by 7 gives 2 with 0 remainder. Hence, June 9 is Sunday.

Religious concerns[]

Calendar reform at the United Nations was adjourned sine die (without fixing a day for future action or meeting) during the UN’s Economic and Social Council’s 905th meeting on 1956 April 20. The reform was objected “because of the undesirable effect it would have on many aspects of religious life—the observance of Sabbath in particular.” [20]

Exodus 20:8, King James Version states: “Remember the sabbath day, to keep it holy.” Sabbath is a religious observance, a special day of prayer, and a day of rest dedicated to God. It was argued that the natural succession of the Friday Sabbath of the Muslims, Saturday of the Jews, and generally Sunday of the Christians would be disturbed leading to difficulties in its religious observance and its sanctity.

In the Aristean calendar, December 31 every year and June 31 every leap year are public holidays throughout the world. For the religious, December 31 is designated as the Grand Sabbath and June 31 as the Glorious Sabbath. The Grand Sabbath is the main or principal Sabbath of the year. It is the day when man gives thanks to God for all His blessings during the year and pray for His blessings for the coming year. The Glorious Sabbath, on the other hand, is a special day every four years when man glorifies God in a very special way by delighting on His magnificence, grandeur, majesty, greatness and splendor.

Jesus said in Mark 2:27-28, King James Version: “The sabbath was made for man, and not man for the sabbath: Therefore the Son of man is Lord also of the sabbath.” By making these two days as Sabbath days, man makes them for his goodness, doesn’t he? Will God not be more pleased by giving Him these extra days as Sabbath days? Hence, the religious objection is answered by an appropriate religious answer, and from Jesus Himself!

The Grand Sabbath and the Glorious Sabbath could become occasions wherein Christians, Jews and Muslims will all observe Sabbath days on the same common days, thereby promoting unity.

Fixed dates of Christian holy days[]

These holy days are for Christians only. Other religions may prepare their own holy days fixed on the Aristean calendar.

  • Start of Christmas Season – May 5, Monday
  • Christmas Eve – May 22, Thursday
  • Christmas Day – May 23, Friday
  • Glorious Sabbath – June 31, No-weekday or Leap Year Day (during leap years)
  • Crucifixion Day – August 17 if actual date or August 15 if actual day of the week
  • Resurrection Day – August 21 if actual date or August 19 if actual day of the week
  • Ascension of the Blessed Virgin Mary to Heaven – September 16, Sunday
  • Ascension of Jesus to Heaven – September 30, Sunday
  • Blessing of the Children – November 25, Sunday
  • Grand Sabbath – December 31, No-weekday or World Peace Day
  • The Sabbath Day of Christians is Sunday.


See also[]

External Link[]