At the end of the 16th century, there were 20,000-25,000 streltsy; in 1681, there were 55,000, including 22,500 in Moscow alone. Streltsy’s engagement in handicrafts and trade led to a significant proprietary inequality among them and their blending with tradesmen. Even though Streltsy demonstrated their fighting efficiency on several occasions, such as the siege of Kazan in 1552, the war with Livonia, the Polish-Swedish invasion in the early 17th century and military operations in Poland and Crimea, in the second half of the 17th century Streltsy started to display their backwardness compared to the regular soldier or reiter regiments (see Imperial Russian Army). Military service hardships, frequent salary delays, abuse on the part of local administration and commanders led to regular Streltsy's (especially the poorest ones) participation in anti-serfdom uprisings in the 17th and early 18th centuries, such as the peasant wars in the beginning of the 17th century and in 1670–1671 (leader – Stepan Razin), urban uprisings (the Moscow uprising of 1682, the Streltsy uprising of 1698, the Bulavin Rebellion of 1705–1706 in Astrakhan).