In 1122, after heavy fighting with the Seljuks that involved at least 60,000 Georgians and up to 300,000 Turks, the troops of the King of Georgia David the Builder stormed Tbilisi. After the battles for Tbilisi concluded with David's victory, he moved his residence from Kutaisi (Western Georgia) to Tbilisi, making it the capital of a unified Georgian State and thus inaugurating the Georgian Golden Age. From 12–13th centuries, Tbilisi became a dominant regional power with a thriving economy (with well-developed trade and skilled labour) and a well-established social system/structure. By the end of the 12th century, the population of Tbilisi had reached 100,000. The city also became an important literary and a cultural center not only for Georgia but for the Eastern Orthodox world of the time. During Queen Tamar's reign, Shota Rustaveli worked in Tbilisi while writing his legendary epic poem, "The Knight in the Panther's Skin". This period is often referred to as the Georgian Golden Age or the Georgian Renaissance