Final answer:
Paul III was a turning point for the papacy as he initiated the Counter-Reformation, addressing church corruption and doctrinal issues, leading to a significant internal purification and a vigorous response to Protestantism.
Step-by-step explanation:
Pope Paul III was an important turning point for reforming the papacy due to his critical role in addressing issues within the Church and initiating the Counter-Reformation. Before the time of Paul III, the Catholic Church faced various challenges including corruption, the selling of church offices known as simony, nepotism, and political power struggles that marred the spiritual reputation of the papacy. Pope Paul III's pontificate marked a departure from these practices as he sought to purify the church and combat the spread of Protestantism through measures like the formation of the Roman Inquisition and the calling of the Council of Trent. These actions profoundly changed the direction of the Catholic Church, steering it towards spiritual renewal and doctrinal clarification.