Pope Gregory XIII (or presumably, mathematically minded monks working for Pope Gregory) came up with a new calendar that would help regulate Easter more reliably. And so in that year, the Catholic ...

Prior to the Gregorian ... days the calendar, including a leap day in February every four years, calendar.com said. Finally, the calendar we all know was adopted by Pope Gregory XIII in 1582.

Pope Francis on Sunday called for a unified Easter date among Christian churches in the spirit of promoting unity. "It is a happy coincidence that Easter in this ecumenical Jubilee Year is celebrated ...

On this day, February 29, conversations the world over may conjure the name of Pope Gregory XIII – widely known ... the one we have today. But the Gregorian calendar isn’t the only legacy ...