He was born Kassa Haile Giorgis, but was more regularly referred to as Kassa Hailu (Ge’ez: ካሳ ኃይሉ — meaning “restitution” and “His [or the] power”). His rule is often placed as the beginning of modern Ethiopia, ending the decentralized Zemene Mesafint (Era of the Princes).

Tewodros II’s origins were in the Era of the Princes, but his ambitions were not those of the regional nobility. He sought to reestablish a cohesive Ethiopian state and to reform its administration and church. He did not initially claim Solomonic lineage but did seek to restore Solomonic hegemony, and he considered himself the Elect of God. Later in his reign, suspecting that foreigners considered him an upstart and seeking to legitimize his reign, he added “son of David and Solomon” to his title.