The shield shows the scene of the battle on the Mulwijski Bridge in 312, fought between the armies of Maxentius and Constantine the Great.
During it, Constantine was to see a cross in the clouds and hear the words: In hoc signo vinces, meaning: "Under this sign you will win." This legend was interpreted as the triumph of Christianity.
The shield was found on September 9, 1679, during the renovation of the chapel of the Holy Cross
in the cathedral church on Wawel hill. For many, she was regarded as an announcement of Sobieski's future victories in the fight against the Turks.
The work of art, which was deposited in the hands of the king, was probably taken on an expedition to Vienna, and later, together with the Vienna trophies, stored in Żółkiew, finally reaching the Czartoryski Museum.