February 27

Constantine, later the first Roman emperor to adopt Christianity and founder of Constantinople, was born at Naissus in the Balkans.

Emperors Theodosius I, Gratian, and Valentinian II issued the Edict of Thessalonica, making Nicene Christianity the official faith of the Roman Empire.

Theodosius II established the Pandidakterion at Constantinople, a state academy of thirty-one chairs teaching grammar, rhetoric, law, and philosophy in Greek and Latin.

Ivan Pavlov, the Russian physiologist whose studies of conditioned reflexes in dogs opened new ground in the science of learning, died in Leningrad.