solar year

Forty-nine years make a convenient luni-solar cycle, reconciling the lunar month and the tropical solar year.

The adjustment of the solar year to correspond with the lunar year and of the two with the civil year dates from this period.

Astronomy was sufficiently understood for the accurate measurement of time in the divisions of the solar year.

Twelve lunar periods, making up approximately the solar year, gave peculiar importance to the number twelve also.

The length of the solar year first accurately determined by Dionysius, in the astronomical canon.