Historically the term "Uyghur" (meaning "united" or "allied") was applied to a group of Turkic-speaking tribes that lived in what is now Mongolia. Along with the so-called Kokturks (also known as Gokturks) the Uyghurs were one of the largest and most enduring Turkic peoples living in Central Asia. They existed as a tribal federation ruled by the Juan Juan from 460–545, and then by the Hephthalites from 541–565 before being taken over by the Gokturk empire (Khaganate).