(Photo: L'Osservatore Romano)Retired Pope Benedict XVI enjoys a beer at his 90th birthday party at the Vatican's Mater Ecclesiae Monastery on April 17, 2017.

Retired Pope Benedict XVI celebrated his 90th birthday in the way that Bavarians often celebrate anniversaries - with a tankard of German beer and some pretzels.

"Thank you for bringing Bavaria here," Benedict told his guests covered by a blue Roman sky flecked with white clouds that he noted "recall the white and blue flag of Bavaria" and how "it's always the same sky."

He was last pope before Francis, and the first to retire from the positon in almost 600 years, born in Bavaria on April 16 which fell on Easter Sunday this year.

A small informal party was held April 17 outside his residence, the Mater Ecclesiae Monastery in the Vatican gardens. Catholic News Service reported.

At that gathering Benedict told his guests that "My heart is full of gratitude for the 90 years which the good God has given me," CNA/EWTN News reported.

His old friend Pope Francis visited him on April 12, to offer him birthday greetings.

Among the special guests at the Bavarian party included were Monsignor Georg Ratzinger, the retired pope's 93-year-old brother; Archbishop Georg Ganswein, the retired pope's personal secretary and Birgit Wansing, a longtime administrative assistant.

Also there was the minister president of Bavaria, Horst Seehofer, and a group of men dressed in the traditional uniforms of the "Schutzen" in dark green wool hats decorated with feathers, pins and sprigs of greenery.

Benedict had been Cardinal Joseph Ratzinger before he was elected as head of the global Catholic Church on April 19, 2005.

He broke with six centuries of tradition in 2013 by stepping down from his post, citing health concerns and prompting the election of Pope Francis, Huffington Post reported.

Benedict was a pope who was perceived of being staunchly conservative and a stickler for the rules.

EWTN.TV asked Archbishop Gänswein, "How is Pope Benedict?"

He answered, "Considering his age, he is remarkably well. He is also in good spirits, very clear in his head and still has a good sense of humor. What bothers him are his legs, so he uses a walker for help, and he gets along very well. And this walker guarantees him freedom of movement and autonomy.

So, for a 90-year old, he is doing pretty well – even though, from time to time, he complains of this or that minor ailment."