Saint Ambrose and Emperor Theodosius, by Anthony van Dyck (1599-1641)
On this day in 63 B.C. the Catilinarian conspiracy continued to take its toll on Republican Rome [See Cicero Thwarted an Assassination Attempt]. A few centuries later -- and barely a half century after Constantine legalized Christianity -- Emperor Theodosius I banned pagan worship in 393. Emperor Theodosius had been tolerant of most pagan practices, but then in 391 he sanctioned the destruction of the Serapeum at Alexandria (the largest Greek temple in Alexandria, dedicated to Alexandria's protector deity, Serapis), enacted laws against pagan practices, and put an end to the Olympic games. He is also credited with putting an end to the power of the Arian and Manichean heresies in Constantinople, while establishing Catholicism as the state religion.