Pope Benedict touched down in his home country of Germany on Thursday, on what is expected to be a difficult visit.
The pontiff received a warm welcome from Chancellor Angela Merkel, President Christian Wulff and members of the German cabinet.
The pontiff will visit mostly Protestant and atheist regions in the ex-communist east and is expected to urge followers not to not to leave the Roman Catholic Church following the clerical sex abuse scandal.
Protesters in East Berlin held an anti-pope demonstration as Benedict began his visit.
Those taking part said they wanted to bring the issue of child abuse cases to the forefront of the pontiff's visit.
(SOUNDBITE) (English) PRESIDENT OF THE SURVIVORS NETWORK OF THOSE ABUSE BY PRIESTS (SNAP) BARBARA BLAINE:
"We believe that the Catholic church officials have done a horrific job and that they continue to harbour sexual predators and that they endanger children across the globe."
The first day of the pontiff's high profile visit was mainly taken up with meeting political leaders such as Chancellor Merkel and addressing the lower house of parliament.
On Friday he plans to meet Protestant leaders in Erfurt, and his tour will end in the mostly Catholic south-western city Freiburg.
Simon Hanna, Reuters.