In the Byzantine civil war which began in 1352, John Palaiologos obtained the help of Serbia, while John Kantakouzenos sought help from Orhan I, the Ottoman bey.[1] Kantakouzenos marched into Thrace to rescue his son, Matthew, who was attacked by Palaiologos shortly after being given this appanage and then refusing to recognize John Palaiologos as heir to the throne.[1]