In 1952, the Indian Calendar Reform Committee convened under the Chairmanship of the famous scientist Meghnad Saha and reported that there existed more than 30 calendar systems in India. The Committee's experts determined that almost all those systems of measuring and dividing time into days, weeks, months, etc. were accurate and that they were based on precise mathematical principles and astronomical observations and measurements. Out of those thirty or so systems, three calendars are very much older than any western calendar. They are:

1. Kaliyuga Calendar,
2. Buddha Nirvaana Calendar, and
3. Vikrama Samvat Calendar.

The fact that these three calendars have been serving the Indian people for millennia without any calculational errors and internal contradictions and that they have been helping Indians to determine dates of seasonal festivals, eclipses, birthdays of sacred persons, etc. with great accuracy, year after year, for millennia, underlines the strength of India's scientific tradition, which is not fully known to most Indians and foreigners alike. These three powerful Indian calendars did not destroy the regional systems such as the Kollam calendar of Kerala, providing a strong evidence for the respect that Indians have had for diversity and the tolerance Indian groups have felt for traditions other than their own.

In the West, the oldest calendar system was that of the Mesopotamians. During the Roman times, a calendar emerged that the Jews and the Greeks had developed combining the Mesopotamian system with the Egyptian calendar. During the reign of Julius Caesar (102 - 44 BC), a calendar was in vogue that had begun in 753 BC. But it was not an accurate one. Its inaccuracy was due to the following reason:

The exact length of the solar year is 365.2422 days. If the length of the year is rounded off as 365 ¼ days, each year the calendar will gain an extra 11 minutes and 14 seconds. This error will grow to a full day every 128 years. By Julius Caesar's time, the difference between the calendric spring solstice and the real solstice had grown to a stupendous three months! Caesar's calendar experts did not know how this error was caused or how to rectify it. Therefore, they proposed an innovation to the emperor: Scrap the old calendar and start a new one beginning with 46 BC. This is how the Julian Calendar came into being.

Error-ridden Julian Calendar

By 1500 AD, the Julian Calendar also became laden with error because the original error in calculation had not been rectified. Pope Gregory's calendar experts found out that the Julian Calendar was totally undependable for determining the exact dates of Jesus Christ's birth, crucifixion and such other holy events and for celebrating them accurately year after year. The Pope's Calendar Reform Commission's chairman was a German Jesuit priest by the name of Christof Clavius (1537 - 1612 AD). He was a mathematician of high caliber and had mastered the entire western mathematical knowledge of that period.

Pope Gregory's Calendar Reform Commission worked hard for several years; yet they were not able to find an error-correction method. Then all of a sudden, something happened: in October 1582, the Commission under the leadership of Father Clavius introduced two reforms. First, to take away 10 days from October 1582. Second, make each year that is divisible by four into a Leap Year in order to compensate for the loss of a day every 128 years. Only one exception was made. Years that end in two zeroes would be considered Leap Years only if they are divisible without remainder by the number 400. For instance, the year 2000 is a Leap Year, but 1900 is not. Thus, the day after October 4,1582 was renamed as October 15, 1582 and thereby the Gregorian Calendar was born. We all now know that the Gregorian Calendar is hanging on almost all the walls of the world's homes after having become widely accepted through the power of colonial rule imposed by European powers in hundreds of countries of the world.

Here a question can be raised. How did Father Clavius's Commission suddenly discover a solution for the problem in the Julian Calendar? Until October 1582, the western calendar experts had tried for hundreds of years to correct the error in the Julian system although they had learnt all the calendar techniques refined by Jews and Muslims. How did in 1582 the riddle get solved as if all of a sudden?

Father Clavius and Namboothiris of Kerala

It is here that the Namboothiris enter the picture. Before that is explained, a little bit of Kerala history needs to be recounted here. On 1498 May 20th, Vasco da Gama arrived in Kozhikode for the first time. His journey from Portugal by sea took two years to complete. Afterwards, a group of Portuguese sailors reached Kozhikode under the leadership of Pedro Cabral on 1500 September 13th. That journey took 17 months. The reason why these journeys took so long was that the Portuguese sailors did not know how to calculate the latitude at sea during day. Therefore the ships sailed slower during day as they did not know if they were going in the right direction. Indian and Arabic sailors could use their calendars and astronomical instruments and determine the latitude even during the day. The technique for determining the latitude by looking at the sun at noon is described in Mahaabhaaskareeyam of Bhaaskaraachaarya I and in the widely popular Laghubhaaskareeyam. For obvious reasons, the Arabs did not share this knowledge with the Portuguese sailors. Yet mathematicians such as Father Clavius were aware of the high level of mathematical and astronomical knowledge in India through reading translations of Arabic books on the two subjects which were often transcreations of Indian books. (The Arab word for mathematics literally means "Hindu Learning").

Could Father Clavius who was headquartered in Rome have connected directly with Indian mathematics? This is, at the moment, a relevant question. It must be remembered that after six years of da Gama's arrival in Kerala, the Jesuit priests who had come from Rome built the first church in Kochi. In 1506, the second church was built by them -Church of Santa Cruz. The third church they built in Kochi (1510) was the Church of Madre Deus (Mother of Jesus Church). Within 40 years a gigantic college with three floors was built by the Jesuits right next to the third church. What was going on in this Jesuit college?

Dr. C.K. Raju, who has studied the archival records of the Jesuits in Goa and Rome, says that between 1550 and 1660, on an average 70 Jesuit priests taught and studied at this college in Kochi every year. Dr. Raju works at the Nehru Memorial Museum, Library, and Cultural Studies Institute in Delhi and is a scholar in Mathematics, Philosophy, Sanskrit, and History of Science. He was also helped by the Latin scholar Dennis Almaida. These two scholars have analyzed the career of one of these Jesuit priests who came to Kochi - Father Mateo Ricci. They say that Father Ricci joined the College of Rome in 1571 and studied Mathematics, Navigational Science, Astronomy, and Cosmology. Father Ricci's dearest professor, Father Clavius, firmly believed in the idea that Jesuit priests should study scientific subjects along with theology. It was Clavius who had reformed the syllabus of studies at the College of Rome and modernized the pedagogy there.

As directed by Professor Fr. Clavius, Father Ricci was delegated to go to India and work to spread Christianity. First he worked in Goa and then in Kochi. The visiting priests at the Kochi Jesuit college studied Malayalam and Tamil as well as topics such as indigenous medicine and folklore. Foreign Jesuits such as Father Ricci also taught the Malayali students subjects such as Latin and Christian theology. Did Ricci seek to accomplish other goals as well?

Role of Namboothiris in the Genesis of the Gregorian Calendar

The following are Dr. Raju's conclusions on the basis of the records he has examined and circumstantial evidence:

1. Fr. Ricci's mission as determined by Fr. Clavius was to search for Indian texts on calendar calculations, to translate the texts into Latin, and to send them to Rome. In four years, Ricci completed his mission in Kochi and as a thirty-year old young priest he left for China. In China too he was engaged in extensive projects of examining Chinese advances in Mathematics.

2. Fr. Ricci also was entrusted with the task of collecting information on navigational techniques so that the length of the journey from Portugal could be reduced. He must have succeeded in this as well, as seen by the steadily decreasing length of Portuguese sea trips to India.

3. The letters sent by the mathematician priest Fr. Ricci to Rome and Goa mention the fact that he was "learning techniques of calendric measurements and calculations from greatly intelligent Braahmanans." [Quoted from Fr. Mateo Ricci's letter written in Latin on 1581 December 1: "Brahmane muito intelligente que saiba as cronicas dos tiempos, dos quais eu procurarei saber tudo"].

4. The Brahmanans mentioned by Fr. Ricci must be Namboothiris of Kerala according to Dr. Raju and Dr. Dennis Almaida. Ricci might have translated the masterpiece of Kerala mathematics and astronomy, Yuktibhaasha written in Malayalam. Along with that he might have sent translations of Kerala scientists such as Madhavan, Parameswaran, and Neelankandhan (Kelalloor Neelakandha Chomathiri). A proof for this can be seen in the following fact: During the years after Fr. Ricci visited Kochi and lived there, European mathematicians such as Galileo, Cavalieri, and Gregoy brought about immense revisions in their own mathematical theories. Most of the scientists of the day had close connection with Jesuit libraries in Rome and elsewhere. In some of the European scientific texts of the period, all of a sudden there began to appear references to Indian mathematical advances.

It will take some more time before western historians of science and scientists start to confess that their scientific advances after the middle ages owe quite a lot to Indian mathematicians and their seminal research. We must remember that most westerners and even scholars call the Indian science of numbers "Arabic numerals." Even now most of them have not discovered the derivative nature of all Arabic mathematics and science and their indebtedness to India and China although many western historians have unearthed the truth in the last few decades. We in India cannot wait for westerners to see the light of truth. We should look into the research work of experts such as Dr. Raju and gain knowledge about the scientific genius of our own ancestors and pioneers and improve our sense of accurate history.

References:

1. Geometry in Ancient and Medieval India - by Dr. T.A. Saraswathi Amma (Motilal Banarsidas, New Delhi, 1999).
2. New Advent Catholic Encyclopedia
3. "India through its Calendars." Article by Amartya Sen, Other, Vol. 1, issue 1
4. "Gregorian Calendar." Article by Albert van Helden, Internet.
5. "The Origins of our Modern Calendar." Article by Linda Kerr, Internet.
6. "Mathematics and Culture." Article by Dr. C.K. Raju, Internet.
7. Portugal, the Pathfider Edited by G.D. Winius (Madison, 1995)
8. "Computers, Mathematics Education, and the Alternative Epistemology of the Calculus in Yuktibhasha." Article by Dr. C.K. Raju, Philosophy East and West, Vol. 51 (2001).