Vaclav Havel, the dissident playwright who turned to politics to help peacefully bring down communism in Czechoslovakia, has died at the age of 75.
His assistant Sabina Dancecova said Mr Havel died this morning at his weekend house in the northern Czech Republic.
Mr Havel was his country's first democratically elected president after the non-violent "Velvet Revolution" that ended four decades of repression by a regime he ridiculed as "Absurdistan".
As president, he oversaw the country's bumpy transition to democracy and a free-market economy, as well its peaceful 1993 break-up into the Czech Republic and Slovakia.
Czech leaders and foreign politicians have begun paying tribute to Mr Havel.
Czech Prime Minister Petr Necas called him "the symbol of 1989" and said he "did a tremendous job for this country".
Mr Necas's deputy, Karolina Peake, called his death "the end of an era, and end of the person who meant so much for the country".
Swedish foreign minister Carl Bildt tweeted that Havel was "one of the greatest Europeans of our age".
The Czech government is expected to meet tomorrow to declare a period of official mourning.
In neighbouring Poland, the founder of the anti-communist Solidarity movement and former president Lech Walesa called Mr Havel "a great fighter for the freedom of nations and for democracy".
"It is a great pity and a great loss. His outstanding voice of wisdom will be missed in Europe," said Mr Walesa, the 1983 Nobel Peace Prize laureate.
In Slovakia, which split from the Czech Republic in 1993, Prime Minister Iveta Radicova said it was Mr Havel who "opened the gates to the world after 1989".
German Chancellor Angela Merkel, who grew up in East Germany and went into politics as communism crumbled, said she learned "with great dismay" of Mr Havel's death.
"His dedication to freedom and democracy is as unforgotten as his great humanity," Ms Merkel said. "We Germans also have much to thank him for."
The president of the European parliament Jerzy Buzek - a former Polish prime minister and activist in Solidarity - wrote on Twitter: "Vaclav Havel is the figure that represents the Velvet Revolution and the reunification of Europe. He will be sorely missed."
In Russia, Grigory Yavlinsky, a veteran opposition figure and leader of the Yabloko party, told the Itar-TASS news agency that Havel "was a man of integrity and dignity who has never been afraid of anyone".
"He devoted his life to freeing his people from a totalitarian regime," Mr Yavlinsky said