We don’t really know when Pope Simplicius was born. Most of what is known about him is that became Pope on February 25, 468.  He defended the Church against the Eutychian heresy at the Council of Chalcedon.  He ended the practice of consecrating bishops only in December.

Simplicius held a synod in Rome, which pronounced anathemas against heretical bishops Peter Fullo, John of Apamea, and Paul of Ephesus.  An anathema is a formal curse by a pope or a council of the Church, excommunicating a person or denouncing a doctrine. He worked to maintain the authority of Rome

In 482, Bishop Gregory of Modena was consecrated a bishop against his will by Archbishop Joannes I of Ravenna. Pope Simplicius criticized the Archbishop for this.  Pope Simplicius was the first pope to carry out consecrations at times other than December and began to confer holy orders in February.  He worked to help the people of Italy against the marauding raids of barbarian invaders. He died on February 24, 483.  Since 1971, his feast day has been March 10.