The Byzantine civil war of 1341–1347, sometimes referred to as the Second Palaiologan Civil War, was a conflict that broke out in the Byzantine Empire after the death of Andronikos III Palaiologos over the guardianship of his nine-year-old son and heir, John V Palaiologos. It pitted on the one hand Andronikos III's chief minister, John VI Kantakouzenos, and on the other a regency headed by the Empress-Dowager Anna of Savoy, the Patriarch of Constantinople John XIV Kalekas, and the megas doux Alexios Apokaukos. The war polarized Byzantine society along class lines, with the aristocracy backing Kantakouzenos and the lower and middle classes supporting the regency. To a lesser extent, the conflict acquired religious overtones; Byzantium was embroiled in the Hesychast controversy, and adherence to the mystical doctrine of Hesychasm was often equated with support for Kantakouzenos.
As the chief aide and closest friend of Emperor Andronikos III, Kantakouzenos became regent for the underage John V upon Andronikos's death in June 1341. While Kantakouzenos was absent from Constantinople in September the same year, a coup d'état led by Alexios Apokaukos and the Patriarch John XIV secured the support of Empress Anna and established a new regency. In response, Kantakouzenos' army and supporters proclaimed him co-emperor in October, cementing the rift between himself and the new regency. The split immediately escalated into armed conflict.