Basil II, as mentioned in the previous post, was a bit of a hard case. But it’s quite surprising that he actually reached adulthood at all.
It’s not historically unusual for a trusted general/grand vizier/uncle of an emperor to seize power. What is unusual is for that to happen and the legal emperor to be not only allowed to live, but retain their (theoretical) position. And it’s double unusual with a side-helping of surprise when this happens twice to the same emperor, who ends up becoming a huge success himself.
The White Death of the Saracens is not the sort of nickname you earn by being a pansy, and Nicephorus II Phocas, Emperor of Byzantium, deserved it. The trajectory of Islamic military history is an upward curve from its founding to the siege of Vienna, but there were occasional blips (and a few serious ruptures) along that thousand year journey.
Romanus II died suddenly in his mid-20s, leaving a power vacuum (although both his children had been crowned co-emperors, they were five and three at the time). Proclaimed by the army as emperor, Nicephorus Phocas marched into Byzantium and became ruler of the Eastern Empire in fact as well as name, aided by his talented nephew (and fellow general) John Tzimisces.
He enjoyed significant success in the East, as might be expected from his nickname, and took the late Romanus’ widow, Theophano, as his lover. However, after a few years another man took Theophano into his bed: John Tzimisces.
Tzimisces had helped Nicephorus to the throne, but had, some time later, been deprived of military command. It proved a fatal decision for the Emperor. Conspiring with Theophano, Tzimisces and others entered the palace late at night. Finding the Emperor’s bed empty, he panicked, only to discover Nicephorus was sleeping on the floor.
Tzimisces kicked him to death, all the while berating his uncle’s ingratitude for the assistance given when he had sought to become emperor.
And then there was the question of Basil and his younger brother Constantine. Bizarrely, they survived a second usurpation of imperial power. They lost neither their lives nor their nominal status, although, being far off adulthood, they had no practical power. It is worth noting that Basil and Constantine were nephews of Tzimisces (and therefore also related to Nicephorus), but also that such a relationship has often failed to stop regicide.
On the battlefield, Tzimisces continued the policy of his predecessor (knocking the stuffing out of the Saracens), and enjoyed similar success. He also died suddenly, possibly due to poisoning. Upon his death, Basil II, just about old enough to become emperor in truth, took on the reins of power. Although he also fought in the East, it was his campaigns in Europe which earnt him his nickname: the Bulgar-Slayer.