Germanos II (1223-40) was the Orthodox patriarch of Constantinople at a critical period after its fall in 1204 to the fourth crusade, when Byzantium looked doomed to irrelevance, as its emperor and patriarch eked out a shadowy existence in exile at Nicaea. Germanos II’s major achievement was to give his office renewed substance by obtaining recognition of his ecumenical authority not only from the community of Orthodox churches, but tacitly from the papacy itself. In doing so he also restored a modicum of prestige to the imperial dignity. Remarkable as his legacy was, it has gone largely unrecognised both by contemporaries and by modern scholarship. Why memory of his work was not better preserved is a puzzle to which his unfairly neglected sermons offer a key. They reveal an abrasive character, whose humble origins put him at odds with both the court nobility and the higher clergy. He was more concerned with the promotion of the evangelical ideal through preaching and social justice than he was with church administration and the performance of the liturgy. He was in conventional terms an embarrassment, who was best forgotten. The twenty-one sermons translated here were not, as was so often the case, exercises in belles-lettres but a sustained effort to bring about both social and moral reform as a precondition for the recovery of Constantinople from the Latins. They bear comparison with those of John Chrysostom, whose influence is evident in the way Germanos II used his sermons to create a dialogue with his audience. This new translation of a neglected source casts light on the surprising survival of Byzantium at a critical moment in its history.