VATICAN CITY – Pope Benedict XVI bestowed his final Sunday blessing of his pontificate on a cheering crowd in St. Peter’s Square, explaining that his waning years and energy made him better suited to the life of private prayer he soon will spend in a secluded monastery than as leader of the Roman Catholic Church.

On Thursday evening, the 85-year-old German-born theologian will become the first pope to have resigned from the papacy in 600 years.

Sunday’s noon appearance from his studio window overlooking the vast square was his next-to-last appointment with the public of his nearly eight-year papacy. Tens of thousands of faithful and other admirers have already asked the Vatican for a seat in the square for his last general audience Wednesday.