WARSAW, May 23 (Xinhua) -- Polish President Andrzej Duda and his Slovenian counterpart Borut Pahor unveiled Wednesday a memorial to Slovenian soldiers fallen in the First World War at a war cemetery in Gorlice, southeastern Poland, Polish Press Agency reported.

In their addresses at the cemetery, which houses graves of Austro-Hungarian, German and Russia soldiers fallen in the May 1915 Battle of Gorlice, both leaders stressed that peace was not granted forever.

"Poland's and Slovenia's freedom was born of the blood of our soldiers, spilt together on the theatres of the First World War. Neither the Slovenians nor we Poles had a country then. We fought arm in arm, but in the Austro-Hungarian army, which was not ours," Duda said, adding that it was necessary to preserve the memory of the First World War and its "terrible hecatomb" for future generations.

Pahor warned against taking peace for granted, observing that it had to be nurtured daily. This, he said, requires avoiding hate speech, showing respect for others and resolving conflicts peacefully.

Pahor also thanked Duda for Poland's help in erecting the Gorlice memorial, saying that the Polish president's presence at its unveiling "a great honour" for him.

According to historians, the Battle of Gorlice, in which combined Austro-Hungarian and German forces together with the Polish Legions broke through Russian lines in Western Galicia, was the biggest and most decisive clash on the First World War's eastern front.