CILLI Or, Cilly.
County in the Windisch Mark on the southeastern borders of the Holy Roman Empire. It was named after its capital, now the town of CELJE in Slovenia, ENE of Ljubljana, northwest of Zagreb, and southwest of Maribor.
The county became important in the later 14th century. In 1402 the daughter of Count William married King Władysław II Jagiełło of Poland and in 1408 the daughter of Count Hermann II married King Sigismund of Hungary, later Holy Roman Emperor (the two Kings had formerly been brothers-in-law, married to the two daughters and heiresses of Louis the Great of Hungary and Poland).
Hermann II was governor of Croatia and Slavonia and inherited the County of Ortenburg with lands in Carinthia and Carniola. He had been with Sigismund at the battle of Nicopolis in 1396, and was granted lands in Zagorje, which lay between the Rivers Drava and Sava in what is today the border region between Slovenia and Croatia.
His grandson Ulric II was a powerful influence in the reign of his young cousin, Ladislas Postumus, King of Hungary and Bohemia and Duke of Austria, but he was murdered in 1456 and his lands passed to the rulers of Austria, who added them to the Duchy of Styria.
Celje passed to Yugoslavia in 1919.