* Wulff is first post-war German president on trial
* Faces corruption charges over 719 euro Oktoberfest visit
* Wulff denies charges, hopes to clear his name in court
Christian Wulff on Thursday became Germany's first post-war president to go on trial, facing corruption charges for accepting more than 700 euros for a hotel stay and meals during an Oktoberfest beer festival when he was a state premier.
Wulff, once seen as one of the country's brightest political talents, served just 20 months as president before he resigned in disgrace last year over accusations he accepted favours before he was elected president in 2010.
Wulff, 54, a former ally of Chancellor Angela Merkel, denied the allegations, saying he hoped to clear his name with a victory in court after rejecting an offer from state prosecutors to settle the case with an out-of-court payment.
"This is certainly not an easy day for me," Wulff told reporters on his way into the court in Hanover, the capital of Lower Saxony where he was the state premier from 2003 to 2010.
"I'm quite confident that I'll be able to clear away the last remaining charges against me," Wulff said.
Wulff's fall from the pinnacle of German politics to the Hanover courtroom dock has fascinated Germans, becoming the subject of countless talk shows and films.
It was also an embarrassment to Merkel, who hand-picked Wulff as her candidate for president in 2010 and stuck with her party ally as the controversy grew to fever pitch.
The scandal also hurt Merkel's Christian Democrats (CDU) and contributed to her party's defeat in the Lower Saxony regional election in January.
Wulff, a rising star in the CDU and a popular regional leader who was once even tipped to succeed Merkel, resigned on Feb. 17, 2012, after prosecutors asked parliament to lift his immunity on suspicion he had accepted undue privileges.
The charges stem from Wulff's visit in 2008 to the Munich Oktoberfest beer festival. Prosecutors say film producer David Groenewold covered his hotel and meal expenses worth 719 euros.
State prosecutors will argue that in exchange Wulff wrote a letter to the chairman of Siemens, on behalf of Groenewold, seeking financial support for one of his film's production entitled "John Rabe", about a war-era Siemens manager in China.
If convicted on the corruption charges, Wulff could face up to three years in jail. The trial, by three judges but no jury, is expected to last until April, with some 22 court dates.
Wulff's reputation had already suffered after Bild daily accused him in 2011 of misleading the Lower Saxony state parliament over a cheap home loan from a businessman friend.
Wulff later expressed regret for misleading the assembly and apologised for threatening the editor of Bild with "war" if he published the story.
Nevertheless, a stream of allegations about flight upgrades, hotel stays and gifts followed, eroding his credibility.
Germans traditionally look to their president, a largely ceremonial office above politics, as a source of moral authority in society and a counterbalance to the government.
After he resigned, East German anti-Communist dissident and rights activist Joachim Gauck was elected president.
Shortly after World War Two, Grand Admiral Karl Doenitz was the first German president put on trial. He was convicted at the 1945/46 Nuremberg military tribunals and spent 10 years in a West Berlin jail.