During the First Serbian Uprising in 1809, Serbian revolutionaries attempted to liberate Niš in the Battle of Čegar. After the defeat of the Serbian forces, the Ottoman commander of Niš ordered the heads of the slain Serbs mounted on a tower to serve as a warning. The structure became known as Skull Tower (). In 1821, the Ottomans arrested the Bishop of Niš, Milentija, as well as 200 Serbian patriots, on charges of preparing an uprising in the Niš area in support of the Greek War of Independence. On June 13 of that year, Bishop Milentija and other Serbian leaders were hanged in public.