Johannes Rau of Germany and his Polish counterpart, Aleksander Kwasniewski, met on a flower-bedecked bridge over the Oder River separating their nations.
"The century that is ending now was a century of war," Rau said later at a ceremony in this Baltic port where the first shots of the war were fired. "Let us work together from this day forward so that at the end of the next century, Poles, Germans and all Europeans can say: The 21st century was a century of peace."
A few hundred war veterans took part in the ceremony beneath a towering concrete monument at Westerplatte, the site of a depot attacked by the German armored ship Schlezwig-Holstein before dawn on Sept. 1, 1939, to signal the start of the Nazi invasion.
Fighting eventually spread through 61 countries on four continents, killing 50 million people and forever changing the world order.
With flags fluttering under clear skies, Kwasniewski and Rau each pledged cooperation and friendship. Most of the veterans and several hundred other spectators supported the calls for reconciliation between neighbors still dealing with lingering problems and animosity from the war.
"I'm so happy to live to this moment that this terrible hatred between our nations is over," said Zofia Gawlicz, 84, who served as a nurse and messenger in the Polish underground.
But one man, a veteran of the Westerplatte battle wearing his Polish military uniform, opposed reconciliation with Germany.
"I will never shake hands with Germans," insisted Wiktor Bialous, 84.
Kwasniewski, a former communist, noted Gdansk was where the war began, but also where the Solidarity movement that toppled communism in Poland was founded. He added that Poland's defeat of communism helped spur the subsequent reunification of Germany, a point echoed by Rau.
"We meet in an entirely different country, a different world, and those who used to be our enemies we consider good neighbors and close partners," Kwasniewski said. "For the first time in our history we have been allies, and I'm proud that I can say more we are friends."
Poland was one of the war's biggest casualties, losing its independence, 6 million of its people and 40 percent of its national wealth. Decades of communist rule established by the Yalta agreement followed the fighting.
Now Poles have democracy 10 years after toppling communism. The reunified Germany has been Poland's strongest foreign investor and was a key supporter for its membership to NATO in March. It also has supported Poland's bid to join the European Union.
The reconciliation between the nations began with former West German Chancellor Willy Brandt, who knelt in penance at the memrial for victims of the Warsaw Ghetto uprising during a 1970 visit. Brandt also signed a treaty with Poland renouncing claims to 40,000 square miles of former German territory incorporated into Poland at the end of the war.
Still, some sticky issues from the war remain unresolved, such as compensation for Poles and other people forced into slave labor by the Nazis, recovering art work stolen from Poland, and property claims by Germans kicked out of territory given to Poland after the war.
"I hope that next year, the year 2000, will close all this stocktaking," Kwasniewski said. "[Reconciliation] takes place in the head, in the heart and in everyday activity. ... It will not be easy or fast."