Close advisors to the Pope have been called Cardinals, from the Latin carde for hinge, since probably the 4th century. Since 1059 Cardinals have served as the exclusive electors of the Popes, and the College itself was given its current form in 1150. Over the centuries the number of Cardinals was held below 70, a biblically significant number, since there were seventy elders assisting Moses in leading Israel and 70 men, besides the Apostles, assisting Jesus in His ministry (Luke 10:1). However, both Pope Paul VI and Pope John Paul II went beyond this number in order to internationalize the College with bishops from around the world. Today there are 117 Electors out of a total of 183 Cardinals, a number which includes those who have reached the age of ineligibility to vote, 80 years.
The College is internally divided into three orders or ranks, Cardinal Bishops, Cardinal Priests and Cardinal Deacons. This division reflects its early history when the advisors and electors of the Pope were taken from the clergy of Rome. Today each Cardinal holds a title, or titular office (i.e. without actual authority), in the Diocese and Province of Rome, such as Cardinal Bishop of Ostia, Cardinal Priest of the Church of Saint John, or Cardinal Deacon of the Holy Names of Jesus and Mary.
The College is presided over by the Dean, who is assisted by a Vice-Dean. Both are elected from the rank of Cardinal Bishops, by their fellow Cardinal Bishops, and confirmed in office by the Pope.