"It is a very good coincidence,” Tusk said, adding that the legacy of the Piast dynasty was especially visible in western Poland.
"It is here that Poland was born, and it is here that the Piast rulers blazed the trail that we are following today," he told the gathering.
Tusk said the regions, commonly referred to as the Western and Northern Territories, are now among the European Union's most dynamic areas.
"The entire world admires Poland as a secure country, increasingly well organised, with a growing economy and with migrants returning not only out of nostalgia," he said.
Tusk spoke ahead of a meeting with other European leaders in Berlin, where talks on efforts to secure a ceasefire in Ukraine were expected later on Monday.
The prime minister said Poland's western regions, shaped by war and postwar displacement, "best understand the value of peace and the price of war."
He said Poland was strengthening its position by building up its military, supporting Ukraine's war effort and taking part in European diplomatic initiatives.
"The lesson of the Western and Northern Territories, the lesson of the tragic war and destruction, commands us to build our own military strength today," Tusk said.
"Poland cannot and will not depend on the whims of neighbours or allies," he added.
Poland’s borders shifted sharply westward after World War II, when the country lost some of its eastern territories, known as the Borderlands, to the Soviet Union and gained territory from Germany in the west and north.