 Theodosius' increasing interest in Christianity, fuelled by the influence of Pulcheria, led him to go to war against the Sassanids (421–422), who were persecuting Christians; the war ended in a stalemate, when the Romans were forced to accept peace as the Huns menaced Constantinople.In 423, the Western Emperor Honorius, Theodosius' uncle, died and the "primicerius notariorum" Joannes was proclaimed Emperor.Honorius' sister Galla Placidia and her young son Valentinian fled to Constantinople to seek Eastern assistance and after some deliberation in 424 Theodosius opened the war against Joannes.