A Cardinal is a senior ecclesiastical leader, considered a Prince of the Church, and usually an ordained bishop of the Catholic Church. The cardinals of the Church are collectively known as the College of Cardinals. The duties of the cardinals include attending the meetings of the College and making themselves available individually or in groups to the pope as requested. Most have additional duties, such as leading a diocese or archdiocese or managing a department of the Roman Curia.
Only Cardinals can become pope. Their major duty is electing a new pope when there is a Papal vacancy.