Bukhara signed a treaty with Russia making Bukhara a Russian protectorate. Khiva became a Russian protectorate in 1873, and the Khanat of Kokand finally was incorporated into the Russian Empire, also as a protectorate, in 1876. By 1876, Russia had incorporated all three khanates (hence all of present-day Uzbekistan) into its empire, granting the khanates limited autonomy. In the second half of the 19th century, the Russian population of Uzbekistan grew and some industrialization occurred. The Jadidists engaged in educational reform among Muslims of Central Asia. To escape Russians slaughtering them in 1916, Uzbeks escaped to China. Soviet Union In the 1940s, Nazi Germany invaded the Soviet Union. In response, many Central Asians, including Uzbeks or Samarkandites, were sent to fight the Germans in the area of Smolensk. However, a number of them, including Hatam Kadirov and Zair Muratov, were captured, transported to the Netherlands, abused and killed. Their bodies were buried in Rusthof cemetery near Amersfoort. For some time, these 101 victims were not identified, apart from the fact that they were Soviets, until an investigation by journalist Remco Reiding. Their plight was also studied by Uzbek historian Bahodir Uzakov of Gouda, South Holland. Witness Henk Broekhuizen said that, despite having seeing them once as a teenager, he would recall the soldiers' faces, whenever he closed his eyes. Moscow's control over Uzbekistan weakened in the 1970s as Uzbek party leader Sharaf Rashidov brought many cronies and relatives into positions of power. In the mid-1980s, Moscow attempted to regain control by again purging the entire Uzbek party leadership. However, this move increased , which had long resented Soviet policies such as the imposition of cotton monoculture and the suppression of Islamic traditions. In the late 1980s, the liberalized atmosphere of the Soviet Union under Mikhail S. Gorbachev (in power 1985–91) fostered political opposition groups and open (albeit limited) opposition to Soviet policy in Uzbekistan. In 1989, a series of violent ethnic clashes, involving Uzbeks, brought the appointment of ethnic Uzbek outsider Islam Karimov as Communist Party chief. Post-Soviet era When the Supreme Soviet of Uzbekistan reluctantly approved independence from the Soviet Union in 1991, Karimov became president of the Republic of Uzbekistan. On August 31, 1991, Uzbekistan declared independence, marking September 1 as a national holiday. Uzbek diaspora Dissident Islamist and anti-Soviet Central Asians fled to Afghanistan, British India, and to the Hijaz in Saudi Arabia. The last Emir of