Relations between the steppe nomads and the settled people in and around Central Asia were marked by conflict. The nomadic lifestyle was well suited to warfare, and the steppe horse riders became some of the most militarily potent people in the world, due to the devastating techniques and ability of their horse archers. Periodically, tribal leaders or changing conditions would cause several tribes to organize themselves into a single military force, which would then often launch campaigns of conquest, especially into more 'civilized' areas. A few of these types of tribal coalitions included the Huns' invasion of Europe, various Turkic migrations into Transoxiana, the Wu Hu attacks on China and most notably the Mongol conquest of much of Eurasia.