Niagara River near Luna Island

: 13 Jun – The Edict of Milan, issued by Constantine the Great and co-emperor Valerius Licinius and establishing religious freedom throughout the Roman Empire, was posted for public view in Nicomedia (313). 13 Jun – The Protestant Reformer Martin Luther married Katharina von Bora, establishing a precedent for married clergy in the Lutheran Church. The Roman Catholic Church, by contrast, required that priests remain unmarried (1525). 13 Jun – Rhode Island became the first British North American colony to ban the slave trade (1774). 13 Jun – German Gotha G bombers raided London during World War I, killing 162 and injuring 432 (1917).