In 1801, the Russian Empire annexed the Georgian kingdom of Kartli-Kakheti (of which Tbilisi was the capital), later cementing its rule with the Treaty of Gulistan of 1813, which ended Iranian control of Georgia. Tbilisi became the center of the Tbilisi Governorate (''Gubernia''). Russian Imperial administrators implemented a new European-style city plan and commissioned new buildings in Western styles. Roads and railroads were built to connect Tbilisi to other important cities in the Russian Empire, such as Batumi and Poti. By the 1850s, Tbilisi once again emerged as a major trade and cultural center. The likes of Ilia Chavchavadze, Akaki Tsereteli, Mirza Fatali Akhundzade, Iakob Gogebashvili, Alexander Griboyedov and many other statesmen, poets and artists all found their home in Tbilisi. The city was visited on numerous occasions by and was the object of affection of Alexander Pushkin, Leo Tolstoy, Mikhail Lermontov, the Romanov family and others. The main new artery built under Russian administration was Golovin Avenue (present-day Rustaveli Avenue), on which the Viceroys of the Caucasus established their residence. For much of the 19th century, Tbilisi's largest ethnic group was Armenian, who, at some point, formed 74.3% of the population.