The Athanatoi were a body of young men that was originally raised by John I Tzimiskes (r. 969-976) in 970 for his war with the Rus', where they played a decisive role in the battles before Preslav and during the Siege of Dorostolon.The unit was commanded by a domestikos, as with most of the other tagmata, and on campaign camped near the imperial bodyguard, the Hetaireia. The contemporary historian Leo the Deacon describes the Athanatoi as heavily armoured shock cavalry, "sheathed in armour" or as "armed horsemen adorned with gold".Tzimiskes' unit was probably disbanded shortly after his death, since it does not appear again in the sources.