Rouran Khaganate ended in 555.

Uyghur Khaganate was created in 742.

Uyghur Khaganate ended in 848.

It depends what you mean by state, but if you mean it in the sense of an organized kingdom, that would be the Kievan Rus, in the late 9th century CE (approximately 880 AD).

However, there were earlier Rus pre-states, which include the old Novgorod principality (also known as Holmgård, after the name the Varangians i.e. Vikings gave to the place) part of a larger association of cities and principalities known as the Russian Khaganate, in the early 9th century AD.

Veljko Rus was born in 1929.