August 15 is widely observed across Europe as the Feast of the Assumption of the Virgin Mary, a major Christian festival commemorating the belief that Mary, the mother of Jesus, was taken up into heaven. The holiday has deep roots in Catholic tradition – it marks Mary’s “ascent to heaven” according to Catholic doctrine. In Eastern Orthodox churches (where it’s often called the Dormition of the Theotokos), August 15 is likewise a central feast day.