50b 63 BC Caesar had been elected Pontifex Maximus,

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 year.^[46] (This Julian calendar was subsequently modified by Pope Gregory XIII in 1582 into the modern Gregorian calendar.) As a result of this reform, a certain Roman year (mostly equivalent to 46 BC in the modern calendar) was made 445 days long, to bring the calendar into line with the seasons.^[46] The month of July is named after Julius in his honour.^[47] The Forum of Caesar, with itsTemple of Venus Genetrix, was built among many other public works.