The heroic defense of Zadwórze near Lwów is one of the most important battles of the 1920s. In this clash, 330 Polish volunteers under the command of Cpt. Bolesław Zajączkowski countered the attack of more than ten times stronger troops of Semyon Budyonny's cavalry army. In the fighting, 318 soldiers died, almost the whole battalion, which was composed mainly of Lwów’s youth. Their fierce resistance prevented the Bolsheviks from conquering Lwów and the march for Warsaw.

"When the fate of the Polish-Russian war and the resurrected Poland was being determined in the deadly Battle of the Vistula River in 1920, Lwów fulfilled the historic role, binding at its forefield the formidable army of Semyon Budyonny. The gravesite of Zadwórze is the evidence of this beautiful role - a symbol of a sacrificial soldier who served the country faithfully to the sacrifice of life" - said Gen. Władysław Sikorski in August 1927, during the ceremony of blessing the cornerstone to commemorate the battle.

The celebration of the 98th anniversary of the Battle of Zadwórze, referred to as the Polish Thermopylae, took place on 18 August 2018 at the foot of the burial mound, where the graves of the heroes of the battle are located. A Holy Mass was celebrated. The young soldiers killed in the battle were commemorated with the Call of the Fallen, the salute of honor and the laying of wreaths.

The celebrations in Zadwórze had state character. They gathered Second World War veterans, activists of the anti-communist opposition, representatives of Polish and Ukrainian authorities, as well as Polish Army soldiers, scouts and Poles from Lwów and the neighbouring area. The letters from the Speaker of the Sejm and the Minister of National Defense were read. The ceremony was attended by the president of the Institute of National Remembrance, Dr. Jarosław Szarek, who made a speech and laid a wreath on behalf of the Institute.

- Generations of the best youth of independent Poland grew up revering the memory of the Lwów Eaglets and the battle of Zadwórze, the Polish Thermopylae - said the President of the Institute of National Remembrance highlighting the importance of the battle and defense of Lwów for Polish history. In his speech he stressed that the memory of these events is becoming alive again, even though it was meant to be erased. - Such solemn homage to the Zadwórze Eaglets of August 1920, for the first time with such a wonderful participation of the Polish Army and young people, is a proof that the memory is coming back - he said. He emphasized that "the return would not be possible without another August, that of the 1980s and the birth of Solidarity. Neither would it be possible without our compatriots in Lwów, who were the guardians of this memory."

At place of the ceremony, young people from the Polish Society for the Care of Military Graves in Lwów and from the Józef Piłsudski Riflemen's Association "Strzelce" were given publications of the Institute of National Remembrance devoted to the Lwów Eaglets and Wilhelmina Adamów's book "When the Golden Horn sounded ... A novel for youth from about November 1918 fights" and the educational game "Semper Fidelis".

Prior to the central celebrations in Zadwórze, the President of the Institute of National Remembrance together with the Polish delegation paid tribute to the city's defenders from almost 100 years ago, who rest at the Cemetery of the Defenders of Lwów. Buried here are, among others, several participants of the battle of Zadwórze with the commander of the battalion captain Bolesław Zajączkowski, on whose grave President Jarosław Szarek laid flowers. The President of the Institute of National Remembrance also laid flowers on the Grave of the Five Unknown from Persenkówka - soldiers who, fighting to defend Lwów, died in this district. The inscription on the grave "Here lies a Polish soldier killed for Homeland" is a copy of the inscription on the Tomb of the Unknown Soldier in Warsaw, where ashes of one of the unknown soldiers rest, taken from the Cemetery of the Defenders of Lwów.