By 1500 the Church badly needed reform. Some bishops lived like princes, many priests were poorly trained, and some preachers sold indulgences as if God's forgiveness could be bought. Many faithful people longed for a holier Church.
In 1517 a German priest and professor, Martin Luther, protested these abuses in his 95 theses. But he went further, rejecting the authority of the Pope, several sacraments and other parts of Catholic teaching. He and other reformers, such as John Calvin, began what became the Protestant churches. In England, King Henry VIII broke away from Rome when the Pope would not let him leave his wife to marry another woman.
Western Christianity split apart, and wars of religion followed. Today the Church teaches that people on both sides were to blame for the division, and that Protestant Christians are truly our brothers and sisters in Christ, joined to us by Baptism. Catholics work and pray for Christian unity; this is called ecumenism.
The Catholic Church answered with true reform. The Council of Trent (1545 to 1563) clearly taught Catholic beliefs: Scripture and Tradition, the seven sacraments, the Real Presence of Christ in the Eucharist, and salvation by God's grace, received in faith and lived out in good works. It founded seminaries to train priests and called for a catechism for teaching the faith.
Saints led the renewal. Saint Ignatius of Loyola, a wounded soldier turned pilgrim, founded the Jesuits, who opened schools and sent missionaries around the world. Saint Teresa of Ávila and Saint John of the Cross renewed the Carmelites and taught the way of prayer. Saint Charles Borromeo reformed his diocese and cared for the sick during a plague.
Meanwhile the Gospel reached new lands. In 1531 Our Lady of Guadalupe appeared to Saint Juan Diego in Mexico, and millions came to believe. Saint Francis Xavier carried the faith to India and Japan. Sometimes missionaries arrived alongside the injustice of colonial powers, and brave Christians such as the friar Bartolomé de las Casas and Saint Peter Claver defended the native peoples and enslaved Africans.