In 1790, Iulon received a princely domain in the Ksani valley after Heraclius II dispossessed the defiant Kvenipneveli dynasty of the duchy of Ksani, dividing it into three parts. Other parts of the duchy were granted to Iulon's half-nephews, Ioane and Bagrat, sons of Crown Prince George, the future King George XII. In addition, in 1794, Iulon was placed in charge of the province of Kartli. At the time of an invasion by the Iranian army of Agha Muhammad Khan in 1795, he was headquartered at Gori and did not take part in fighting which devastated Heraclius's capital, Tbilisi.