(Reuters) - Pope Benedict visits his native Germany from Thursday for the third time since becoming head of the Catholic Church in 2005.
Below are some key facts about his visit:
Born Joseph Ratzinger in Bavaria in 1927, he was a liberal theologian at the Second Vatican Council (1962-1965) but later became a conservative theology professor. Named archbishop of Munich and Freising in 1977, he became a cardinal and in 1981 was appointed Prefect of the Congregation for the Doctrine of the Faith, a key position in the Vatican.
The 84-year-old pontiff has visited Germany twice since his election in April 2005. Four months later, he visited Cologne for World Youth Day and condemned anti-semitism during a synagogue visit.
In 2006 he toured Bavaria and held a speech in Regensburg which angered Muslims around the world with comments seen as depicting Islam as an intolerant and violent religion.
In 2009, he readmitted a Holocaust-denying bishop into the Church, earning a rare reprimand from Chancellor Angela Merkel's
Martin Luther launched the Reformation in the early 16th century as a protest against corruption in the Catholic Church. He wrote his "95 Theses" against indulgences in 1517 and later translated the Bible into German, which both spread his view of the faith and helped develop the modern German language.
About 240,000 people will attend ceremonies with the pope.
In Berlin, he meets Merkel on Thursday Sept 22nd, talks with Muslim and Jewish leaders, speaks to the Bundestag (lower house of parliament) and holds Mass at the Olympic Stadium.
About 100 MPs plan to boycott his speech and instead join protests of up to 20,000 people led by gay and lesbian groups.
On Friday Sept 23rd, he meets Protestant leaders in a monastery in the eastern German city of Erfurt where Luther once lived as a Catholic monk. He also visits the Catholic enclave of Etzelsbach nearby.
On Saturday Sept 22nd he holds an open-air mass in Erfurt before traveling to the largely Catholic southwestern city of Freiburg. He meets former Chancellor Helmut Kohl with whom his predecessor John Paul walked through Berlin's landmark Brandenburg Gate in 1996 to celebrate their role in Germany's reunification.
On Sunday, Benedict meets judges of Germany's Constitutional Court, meets the Catholic community and holds mass before departing.
Much criticism in Germany has been made of the cost of the visit. The Catholic Church says it will spend about 25 million euros but policing the visit will be at German expense.