The Union of Florence was a significant agreement reached in 1439 during the Council of Florence, which aimed to reconcile the differences between the Roman Catholic Church and the Eastern Orthodox Church. This union sought to address theological disputes and promote unity among Christians, particularly in light of the growing threat from the Ottoman Empire. Despite the initial enthusiasm, the Union of Florence faced strong opposition from many Orthodox Christians, particularly in regions like Greece and Russia. Ultimately, the agreement failed to achieve lasting unity, and the schism between the two branches of Christianity persisted, influencing religious and political dynamics in Europe and the Eastern Mediterranean for centuries.