Proleptic Julian calendar with year 0 corresponding to 1 BC, and "year −1" corresponding to 2 BC, so that in this system, Julian leap years have a number divisible by four. The determination of leap years in the proleptic Julian calendar (in either numbering) is distinct from the question of which years were historically considered leap years during the Roman era, due to the leap year error: Between 45 BC and AD 4, the leap day was somewhat unsystematic. Thus there is no simple way to find an equivalent in the proleptic Julian calendar of a date quoted using the Roman pre-Julian calendar
Military campaigns of Julius Caesar succession. Caesar tightly regulated the purchase of state-subsidised grain and reduced the number of recipients to a fixed number, all of whom were entered into a special register. From 47 to 44 he made plans for the distribution of land to about 15,000 of his veterans. In 63 BC Caesar had been elected Pontifex Maximus, and one of his roles as such was settling the calendar. A complete overhaul of the old Roman calendar proved to be one of his most long lasting and influential reforms. In 46 BC, Caesar established a 365-day year with a leap year every fourth