Lithuania has been inhabited since the 10th millennium BC, with agriculture developing in the 3rd millennium BC. Baltic tribes settled in the area around 2000 BC. In the 13th century AD their lands came under threat from two German religious orders, the Teutonic Knights and the Livonian Brothers of the Sword, prompting several of the tribes to establish a defensive union. The union defeated the Livonians in 1236 and in 1250 its leader, Mindaugas, signed a peace treaty with the Teutonic Order.