The papal conclave of 2005 was convened to elect a pope, the leader of the Catholic Church, to succeed Pope John Paul II following his death on 2 April 2005. In accordance with the apostolic constitution Universi Dominici gregis, which governed the vacancy of the Holy See, only cardinals who had not passed their 80th birthday on the day on which the Holy See became vacant (in this case, cardinals who were born on or after 2 April 1925) were eligible to participate in the conclave. Although not a formal requirement, the cardinal electors invariably elected the pope from among their number. The election was carried out by secret ballot (). Of the 183 members of the College of Cardinals at the time of John Paul II's death, there were 117 cardinal electors who were eligible to participate in the subsequent conclave. Two cardinal electors did not participate, decreasing the number in attendance to 115. The number of votes required to be elected pope with a two-thirds supermajority was , or (only in the event of a protracted deadlock) a simple majority of . Of the 115 attending cardinal electors, 5 were cardinal bishops, 93 were cardinal priests, and 17 were cardinal deacons; 2 had been created cardinals by Pope Paul VI and 113 by Pope John Paul II; 24 worked in the service of the Holy See (such as in the Roman Curia), 73 were in pastoral ministry outside Rome, and 18 had retired. The oldest cardinal elector in the conclave was Marco Cé, at the age of , and the youngest was Péter Erdő, at the age of . Another 66 cardinals were ineligible to participate in the conclave, for reasons of age. The cardinal electors entered the Sistine Chapel to begin the conclave on 18 April 2005. On 19 April, after four ballots over two days, they elected Cardinal Joseph Ratzinger, Prefect of the Congregation for the Doctrine of the Faith, who took the papal name Benedict XVI. Cardinal electors The College of Cardinals is divided into three orders: cardinal bishops (CB), cardinal priests (CP) and cardinal deacons (CD), with precedence in that sequence. This is the order in which the cardinal electors process into the conclave, take the oath and cast their ballots. For cardinal bishops, except the Eastern Catholic patriarchs, the dean is first in precedence, followed by the vice-dean and then by the rest