Everything you probably didn't know about former Pope Benedict XVI as he turns 90

Joseph Ratzinger was often described as conservative, aloof and shy. So how could the modest theologian ever conquer the hearts of Catholics around the world and lead the Church? After his appointment, the professor continued to prefer quiet study to the media hoopla. But by the time he addressed the crowd at World Youth Day in Cologne in 2005, he had learned how to inspire the masses.

There had never been two popes in a photo. And not since 1415 had a pope resigned. In 2013, Benedict XVI announced that he was not going to remain in office until his last breath. It was a disputed decision. His successor, however, said it was a courageous step. Pope Francis I appreciates his colleague as an "outstanding theologian" and a "man who really believes."

Benedict XVI's predecessor, John Paul II, held the papacy for 26 years. There was scarcely a country whose soil he had not kissed. But although the German pope had a very different nature, he soon traveled to 24 countries - and made a surprisingly good impression. In Latin America, he even inspired Fidel Castro and brother Raul - Good Friday has since been a public holiday in socialist Cuba.

"As soon as the first notes resounded from Mozart's 'Coronation Mass,' the heavens practically opened and you experienced, very deeply, the Lord's presence," said an enthused Benedict XVI, a great lover of classical music and himself a passionate pianist. Mozart remains his favorite composer. "Mozart is beautiful as God's creation is beautiful."

Red shoes have long been part of the pope's official attire, a tradition stretching back to the Roman Empire. The red is a reminder of Christ's blood on the cross. Like his predecessor John Paul II, Benedict XVI's footwear was handmade by an Italian shoemaker. He also ordered a pair red of red hiking boots.

The pope might himself have drunk a small beer at the most. However, after he was elected to the papacy, Benedict XVI's Bavarian origins inspired an ingenuous brewery to serve up the first papal beer.

The brothers Josef and Georg Ratzinger were both ordained into the priesthood in 1951. Josef became a theology professor, Georg the director of the Regensburg Cathedral Choir. Despite the former's papal office, the intimate relationship between the brothers remained. They are said to have phoned each other at least once a week - and now also go on holiday together.

There is hardly a job that is more demanding than the highest office in the Catholic church: addressing audiences, a permanent media presence, traveling abroad. During the little free time, one might suspect the pontiff rests and relaxes. Not so for Benedict XVI. In his spare moments, the pope wrote a theological trilogy about Jesus that ended up on worldwide bestseller lists.

It was not like him to prefer a particular saint. In his sermons, however, a few more frequently appear, such as St. Augustine, before whose remains he once prayed. Speaking to a general audience, Benedict XVI said, "St Augustine was a man who never lived superficially; his thirst - his restless and constant thirst - for the truth is one of the basic characteristics of his existence."

"Thank you and good night": these were Benedict XVI's last official words on February 28, 2013. The day before, he and thousands of believers took part in large ceremonies. There were tears, calls of Pope "Benedetto," and the waving of flags from all over the world. Now "Papa emeritus" lives in the Vatican monastery, Mater Ecclesiae, fulfilling his wish to continue to serve God in constant prayer.