Cardinal Ratzinger on April 16 turns 75, the mandatory retirement age for a bishop, according to canon law.
He told a seminar over the weekend in Italy that he has a "very hard rhythm of life," and awaits "impatiently the day I will be able to dedicate himself only to writing."
Cardinal Ratzinger rose to prominence during the Second Vatican Council, in which he participated as assistant to Cardinal Joseph Frings, archbishop of Cologne.
Beginning in 1969, Ratzinger was professor of dogmatic theology and the history of dogmas at the University of Ratisborn, where he became vice president. Pope Paul VI appointed him bishop of Munich in 1977, and John Paul II called him to Rome on Nov. 25, 1981, naming him prefect of the Congregation for the Doctrine of the Faith.
Cardinal Carlo Maria Martini of Milan has also announced that he will retire next year. He turns 75 in February.