They agreed to consider new astronomical researches in the evaluation of sighting reports. Organised by the Mecca-based Fiqh (Islamic jurisprudence) Council under the World Muslim League, the conference was chaired by the grand mufti of Saudi Arabia and addressed by its minister of auqaf (endowments).

The Islamic calendar is a manifestation of close interaction between science, syariah and society. Due to confusion over the scientific aspects, Islamic calendar practices underwent problems about 50 years ago, resulting in the use of differing methods of calculations among the countries.

In the 1970s and 1980s, when moon-sighting was done, it was a common to see confusion over the date of Hari Raya Aidilfitri or the start of Ramadan. The starting date of Ramadan would also vary from one country to another within the region, and at times, among the states in Malaysia.

That is now history. Today, in Malaysia and elsewhere in the Muslim world, national calendars reflect the important dates. We have reached this stage after rigorous scientific work over 40 years, initiated by Malaysia through a multipronged International Islamic Calendar Programme.

Also, given the spread of Muslims to all parts of the world in the post-colonial period, by the 1970s, it had become necessary to internationalise the Islamic calendar for use in modern times. A major development was the successful research work in Malaysia, which led to the discovery of the International Lunar Datelines.

The World Conference on the International Islamic Calendar, held in Penang and participated by representatives from the Organisation of Islamic Cooperation, Comstech (the OIC's standing committee on scientific and technological cooperation), Ifstad (Islamic Foundation for Science, Technology and Development), Rabeta Alam Al Islami (World Muslim League), Malaysian Islamic Development Department (Jakim) as well as government agencies and organisations, led to the initiative for the establishment of a global unified international Islamic calendar.

Behind the phenomenal success lies a critical decision by Malaysia and other countries in the region (Indonesia, Brunei and Singapore), followed by those in the Indian subcontinent, North Africa, Europe, the American continent as well as Saudi Arabia and the Middle Eastern countries, to seal the pact on the use of a new unified Islamic calendar worldwide. This was to implement the Penang Declaration adopted by the OIC and supported by the world conference on the use of a unified Islamic calendar system based on imkane ruyah (expected visibility calculations). The move to standardise the system in all countries has begun.

It was during Prophet Muhammad's last pilgrimage in the 10th year of Hijrah that the decision to introduce a lunar Islamic calendar was made, according to the following Quranic injunction:

The number of months;

In the sight of Allah is 12 (in a year);

So ordained by Him the day He created;

The heavens and the earth; Of them four are sacred;

That is the straight usage.

(Al Quran: 9:36)

Several scientists were invited to the Mecca meeting to brief the ulama and myself, who is responsible for the 40-year-old International Islamic Calendar Programme and the establishment of a unified Islamic calendar. A set of resolutions were adopted to facilitate it, one of which is to set up a programme to educate the ulama on the basics of calendrical science by Rabeta Alam al Islami.

Professor Dr Mohammad Ilyas, founder, International Islamic Calendar Programme, and visiting professor, Universiti Malaysia Perlis