Helmut Schmidt, who served as West German Chancellor from 1974 to 1982, has died aged 96, his office says. Mr. Schmidt, who was a Social Democrat, was an architect of the European Monetary System, which linked EU currencies and helped pave the way to the euro. He also helped to consolidate Germany's post-war economic boom.
Chancellor Angela Merkel hailed him as a political institution in Germany. He is seen as one of the most popular German leaders since WWII.
Mr. Schmidt died on Tuesday afternoon in his home city of Hamburg, his doctor Heiner Greten was quoted as saying by German media.
In a televised tribute, Ms Merkel said her predecessor was an authority whose advice and judgment meant something to me. She said Germans had developed a deep affection for him and were impressed by his personal humility as well as his sense of duty.
Reacting to the news, European Parliament President Martin Schulz said he was deeply affected by the death. He was an outstanding chancellor, his death marks a turning point for Germany and Europe, he said.
European Commission President Jean-Claude Juncker said Mr. Schmidt was a special man whose political courage has moved many.
Paying tribute to Mr. Schmidt, French President Francois Hollande described him as a great European.
He was a man who, until his final breath, knew how to give a speech and especially to tell Germans that they had a role to play... that it was within Europe that they should act, Hollande said.
Helmut Schmidt was a far-sighted strategist who lived to see his ambitions for Germany fulfilled in 1990. By 1972, Mr Schmidt was finance minister in the government of Willy Brandt, a brilliant manager of the economic miracle. Two years later he himself was chancellor.
The Berlin Wall dividing West and East Germany was the front line in a dangerous Cold War at the time. With skilled diplomacy, Mr. Schmidt pursued detente with communist leaders on the other side, but when the Soviet Union stepped up the arms race, he stood firm.
Braving fierce protests at home, he let the United States deploy medium-range nuclear missiles on West German soil to keep the military balance.
Strongly pro-European, Mr. Schmidt together with French leaders launched the European Monetary System in 1979. This later paved the way for the Euro.
He will also be remembered for leading his country through a period of political violence in which groups - such as the Red Army Faction - carried out bombings and kidnappings, our correspondent says.
In 1982, the coalition led by Mr. Schmidt's party collapsed and he lost power to Helmut Kohl.
Born in a tough, working-class district of Hamburg in 1918, a month after the end of World War I, Helmut Schmidt spent his early years in a Germany wracked by political, economic and social strife.
Aged 14 when the Nazi Party came to power, he became a group leader in the Hitler Youth, joined the German army in 1937 and, during World War II, saw action on both the eastern and western fronts.
Promoted to first lieutenant rank and the recipient of an Iron Cross, Helmut Schmidt was captured by the British after the Battle of the Bulge in the winter of 1944-45.
While in captivity, his fellow prisoners of war convinced him to become a Social Democrat. Joining the party on demobilisation in 1946, he progressed effortlessly through its ranks.
He graduated from Hamburg University in 1949, having been national chairman of the Social Democrats' student wing, and became an economic adviser to the Hamburg government.
He was elected to the federal parliament in 1953, where his verbosity soon earned him the nickname Schmidt-Schnauze (Big Mouth Schmidt)