Hans-Jochen Vogel, the former leader of Germany's centre-left Social Democrats who once tried to take on Helmut Kohl for the chancellorship, died at the age of 94 on Sunday.
Chancellor Angela Merkel led the tributes, praising Vogel on Twitter as "one of the defining political figures" of postwar Germany whose achievements were "an inspiration and an example" to many.
The SPD party issued a statement calling Vogel "a great Social Democrat" who worked tirelessly for "a just world and a unified Europe".
Vogel, who began his career as Munich's youngest mayor in 1960, towered over German politics for decades and was often described as the centre-left's "moral conscience".
As a young man he served in Adolf Hitler's Wehrmacht and was captured by the Americans during World War II.
After the war he studied law and joined the SPD. As mayor of Munich, he played a key role in bringing the Olympic Games to the city in 1972.
He then switched to national politics and served as minister for regional planning and building as well as justice minister.
In the 1983 general election, Vogel was the SPD's candidate for chancellor but he lost to political heavyweight Helmut Kohl of the centre-right CDU.
Vogel headed the SPD from 1987 to 1991, including during the turbulent time of the fall of the Berlin Wall and German reunification.
He was also leader of the SPD's parliamentary group in the Bundestag.
Vogel retired from politics in 1994 and suffered from Parkinson's disease in his final years.
German President Frank-Walter Steinmeier said the veteran politician was admired across party lines for his integrity and sense of duty.
"Hans-Jochen Vogel worked and fought for tolerance, respect and a peaceful society," Steinmeier said.
"His voice will be missed."