This Calendar was carried by the Mongols into all their dominions, and it
would appear to have long survived them in Persia. Thus a document issued
in favour of Sir John Chardin by the Shaikh-ul-Islam of Ispahan, bears
the strange date for a Mahomedan luminary of "The year of the Swine." The
Hindus also had a 60-year cycle, but with them each year had an
independent name.
The Mongols borrowed their system from the Chinese, who attribute its
invention to the Emperor Hwang-ti, and its initiation to the 61st year of
his reign, corresponding to B.C. 2637. ["It was Ta-nao, Minister to the
Emperor Hwang-ti, who, by command of his Sovereign, devised the sexagenary
cycle. Hwang-ti began to reign 2697 B.C., and the 61st year of his reign
was taken for the first cyclical sign." P. Hoang, Chinese Calendar; p.
11. - H. C.] The characters representing what we have called the ten
coefficient epithets are called by the Chinese the "Heavenly Stems"; those
equivalent to the twelve animal symbols are the "Earthly Branches," and
they are applied in their combinations not to years only, but to cycles of
months, days, and hours, such hours being equal to two of ours.
