His father was poisoned to death, leaving Temüjin under the control of his older brothers, one of whom he soon killed during an argument. By 19, he was married to his first and most important wife, Borte, who was later kidnapped. This was pretty common among the Mongols. Temüjin's mom had also been kidnapped. In rescuing his wife, Temüjin proved his military mettle and he soon became a leader of his tribe, but uniting the Mongol confederations required a civil war, which he won, largely thanks to two innovations. First, he promoted people based on merit rather than family position, and second, he brought lower classes of conquered people into his own tribe while dispossessing the leaders of the conquered clans. Thus, he made peasants love him.