Consequently, he lived abroad for more than thirty years.[4] He pronounced an anathema against Mengistu Haile Mariam and the members of the regime, and then went into exile. Abune Mathias eventually settled in Washington, D.C., where he presided over an Ethiopian Orthodox Tewahedo Church made up of exiles who had fled the Ethiopian revolution, and continued to broadcast messages against the Derg regime on Voice of America.