Galerius was a Roman Emperor who ruled from 305 to 311 AD. He was born around 250 AD in the region of Thrace and became a prominent military leader. Galerius was part of the Tetrarchy, a system established by Diocletian to manage the vast Roman Empire by dividing it into four regions, each ruled by a co-emperor. Galerius is known for his role in the persecution of Christians, which intensified during his reign. However, in 311 AD, he issued the Edict of Toleration, which granted Christians the freedom to practice their faith. His reign marked significant changes in the Roman Empire's approach to religion.