After the establishment of the Roman Republic, years began to be dated by consulships and control over intercalation was granted to the pontifices, who eventually abused their power by lengthening years controlled by their political allies and shortening the years in their rivals' terms of office. Having won his war with Pompey, Caesar used his position as Rome's chief pontiff to enact a calendar reform in 46BC, coincidentally making the year of his third consulship last for 446days. In order to avoid interfering with Rome's religious ceremonies, the reform added all its days towards the ends of months and did not adjust any nones or ides, even in months which came to have 31days. The Julian calendar was supposed to have a single leap day on 24 February (a doubled or ) every fourth year, but following Caesar's assassination the priests figured this using inclusive counting and mistakenly added this bissextile () day every three years. In order to bring the calendar back to its proper place, Augustus was obliged to suspend intercalation for one or two decades. The revised calendar remained slightly longer than the solar year; by the 16th century the date of Easter had shifted so far away from the vernal equinox that Pope Gregory XIII ordered the calendar's adjustment, resulting in the Gregorian calendar.