Pope Saint Celestine V reigned a mere five months. The primary objective of his pontificate was to reform clergy. He abdicated on 13 December 1294, the last pope to do so until Pope Benedict XVI.
Little is known of Pope Saint John I's life before he took office as pope, except that he was born in Tuscany. After a journey to Constantinople concerning Ariansism, he was arrested by Theordric, Arian king of the Ostrogoths. Worn out by his journey and probably starved, John died in prison soon after. Pope St. John I is honored as a martyr.
Pope Saint Pius V (1566-1572) was a Domincan. He called the Council of Trent, Excommunicated Elizabeth I of England for schism, was the patron Palestrina, and organized the Holy League for the defense against the Ottomans at the Battle of Lepanto.
Pope Saint Cletus, the third Pope, governed the Roman Church from about 76 to about 88 during the reigns of the Emperor Vespasian and of Domitian.
We have little definite information about Pope Saint Caius. Iit was said that he was a relative of the Emperor Diocletian and was also an uncle of an unidentified holy Susanna. He also made up the final structure of the lower orders.
Pope Saint Leo IX (1049-1054) worked for reform in the Church chiefly against simony, concubinage, and lay investiture. Upon his election to the Papacy he entered Rome as a simple traveler, and became known as the Pilgrim Pope.
Pope Saint Anicetus, the 11th pope, succeeded St. Pius towards the year c. 153, and reigned till about 168. He condemned Montanism, conferred with St. Polycarp on the Paschal date controversy, and forbade priests from growing their hair. He was martyred and is venerated on April 17.
Pope Saint Martin I (649-55) convened a council which condemned the teaching of Monothelism. The Byzantine emperor sent soldiers to kidnap the Pope from the Lateran Basilica. He died shortly thereafter, tortures and cruel treatment having taken their toll. He is the last of the early popes to be venerated as a martyr.
Pope Saint Simplicius reigned when the last of the western Roman Emperors fell in 476 a.d.. He defended the action of the Council of Chalcedon against the Eutychian heresy, labored to help the people of Italy against the marauding raids of barbarian invaders. He worked to maintain the authority of Rome in the West.
Pope St. Hilarius (d. 468) had been a trusted aide to Pope Saint Leo the Great. Papal legate. As pope, Hilarius confirmed the work of several general councils, rebuilt and remodeled many churches, fought Nestorianism, and held several Councils at Rome.