The Lviv palace of Prince Stanisław Lubomirski was built in the 1760s to Jan de Witte's design on the site of several older houses. The palace's main façade, featuring decoration by Sebastian Vessinger, is on the Market Square. The two other fronts are considerably less conspicuous.
Between 1771 and 1821, the Lubomirski Palace served as the residence for Austrian governors of Galicia. It was purchased by a Ukrainian organization, Prosvita, in the 19th century and subsequently became a hotbed of nationalist activities. It was there that Yaroslav Stetsko proclaimed Ukraine's independence several days after Nazi Germany's invasion of the Soviet Union.
Wikipedia https://en.wikipedia.org/wiki/Lubomirski_Palace,_Lviv
Address 9 Rynok ploshcha, Львів, Ukraine
Coordinates 49°50'30.48" N 24°1'59.88" E