February 23

Roman authorities razed the newly built Christian church at Nicomedia on the feast of the Terminalia, opening Diocletian's decade-long persecution.

Emperor Justinian I laid the foundation stone of the new Hagia Sophia in Constantinople, weeks after the earlier church burned during the Nika riots.

Pope Eugene IV, who convened the Council of Florence, died in Rome after a pontificate of nearly sixteen years.

Carl Friedrich Gauss, the German mathematician and astronomer whose work spanned number theory, geometry, statistics and physics, died in Göttingen.