Eduard Shevardnadze, a former president of Georgia and Soviet foreign minister, died after a long struggle with illness, his personal assistant said.
He was always quick to find a way of connecting with different people, with youngsters and the older generation. He had a bright character, a Georgian temperamen.
Shevardnadze's assistant, Marina Davitashvili, told the Reuters news agency the 86-year-old died on Monday afternoon.
Shevardnadze played a vital role in ending the Cold War as Soviet foreign minister and went on to lead his native Georgia in the stormy early years after independence before being ousted in street protests.
The last Soviet president, Mikhail Gorbachev, expressed sorrow over the passing of a "friend", hailing him as an "extraordinary, talented person" who had done much to bring down the Berlin wall and end the nuclear arms race.
"He was always quick to find a way of connecting with different people, with youngsters and the older generation. He had a bright character, a Georgian temperament," he said, referring to Shevardnadze's passionate nature.
Russian President Vladimir Putin offered his condolences to his "family, as well as the Georgian people".
Loved by some but hated by others in his native Georgia after bringing stability but failing to tackle widespread corruption, Shevardnadze rarely ventured out of his hill-top residence during his last years.
As foreign minister under Gorbachev, Shevardnadze oversaw the thaw in relations with the West before the Berlin Wall came down and the Soviet Union was dismantled.
He was one of the intellectual fathers of "perestroika", or restructuring, the reform policy which Gorbachev said was conceived during a stroll along the shores of the Black Sea with his Georgian comrade.
After the Soviet Union collapsed, Shevardnadze returned to Georgia to become president and brought some stability to the republic after a period of anarchy.
He was toppled in the country's 2003 Rose Revolution when parliament was stormed by protesters.
"I see that all this cannot simply go on. If I was forced tomorrow to use my authority it would lead to a lot of bloodshed," he said when he stepped down in November of that year.
"I have never betrayed my country and so it is better that the president resigns."