Who: Julius Caesar

When Julius Ceasar came to power, he found the Roman calendar in a state of complete confusion and seasons not in their proper months; the Roman calendar was then 335 days long.

Ceasar sought the advice of the Alexandrian astronomer Sosigenes, who suggested that the true length of the year be adopted as 365 and a quarter days.

Ceasar then decreed that the year should usually consist of 365 days. Every fourth year, an extra day should be added at end of February.

Julius Caesar was a great calendar maker.