They knew how to party

The Bulgars were a Turkic people, a branch of which had settled in the lower Danube basin, dominating the local Slavic peasantry. Under the pagan Khan Krum in 811 they defeated a Byzantine army and killed the emperor, making a drinking cup of his skull.

-- Ronald Findlay & Kevin H. O'Rourke, Power and Plenty, p. 14

How to be imposing, in three easy steps:

1) Be given, or preferably take, the name "Khan Krum."

2) Kill the Emperor of the remnants of Rome in the East.

3) When someone asks where you got that charming coffee mug, tell them the truth.