The latest Julian diary try the newest model utilized by the new Western industry for hundreds of years Go into Pope Gregory XIII, who calibrated next. His Gregorian diary took perception in the late 16th century. It remains in use now and you will, obviously, isn’t really finest otherwise there would be no need to have leap 12 months. However it are a massive upgrade, reducing float to help you seconds. As to the reasons did he step-in? Better, Easter.