Pope Francis has marked the 88th birthday of Benedict XVI by offering morning Mass for the Pope Emeritus. According to Vatican Radio, the Pontiff said: "I would like to remind you that today is the birthday of Pope Benedict XVI. I offered Mass for him and also invite you to pray for him, that the Lord will sustain him and give him a lot of joy and happiness." The Pope Emeritus was born on April 6 1927 in Marktl, southern Germany. He was elected pope on April 19 2005 and formally resigned on February 28 2013. His personal secretary said this week that Benedict XVI has not written any theological works since his resignation. In an interview with the Italian newspaper La Repubblica, Archbishop Georg Gänswein said the Pope Emeritus told him: "If I still had the strength to write, I would not have given up the papacy."