<P> In medieval Iceland, a calendar was introduced in the 10th century . While the ancient Germanic calendars were based on lunar months, the new Icelandic calendar introduced a purely solar reckoning, with a year having a fixed number of weeks (52 weeks or 364 days). This necessitated the introduction of "leap weeks" instead of the Julian leap days . </P> <P> During the Mughal rule, land taxes were collected from Bengali people according to the Islamic Hijri calendar . This calendar was a lunar calendar, and its new year did not coincide with the solar agricultural cycles . According to some sources, Mughal Emperor Akbar asked his royal astronomer Fathullah Shirazi to create a new calendar by combining the lunar Islamic calendar and solar Hindu calendar already in use, and this was known as Fasholi shan (harvest calendar). According to Amartya Sen, Akbar's official calendar "Tarikh - ilahi" with the zero year of 1556 CE was a blend of pre-existing Hindu and Islamic calendars . It was not used much in India outside of Akbar's Mughal court, and after his death the calendar he launched was abandoned . However, adds Sen, there are traces of the "Tarikh - ilahi" that survive in the Bengali calendar . Some historians attribute the Bengali calendar to the 7th century Hindu king Shashanka . </P> <P> Of all the ancient calendar systems, the Maya and other Mesoamerican systems are the most complex . The Mayan calendar had 2 years, the 260 - day Sacred Round, or tzolkin, and the 365 - day Vague Year, or haab . </P> <P> The Sacred Round of 260 days is composed of two smaller cycles: the numbers 1 through 13, coupled with 20 different day names: Imix, Ik, Akbal, Kan, Chicchan, Cimi, Manik, Lamat, Muluc, Oc, Chuen, Eb, Ben, Ix, Men, Cib, Caban, Eiznab, Cauac, and Ahau . The Sacred Round was used to determine important activities related to the gods and humans: name individuals, predict the future, decide on auspicious dates for battles, marriages, and so on . </P>

Who came up with 365 days in a year