The Battle of Pelagonia takes place in September 1259, between the Empire of Nicaea and the Despotate of Epirus, Sicily and the Principality of Achaea.

It is a decisive event in the Near East history, ensuring the Byzantine reconquest of Constantinople and the end of the Latin Empire in 1261, and marks the beginning of the Byzantine recovery of Greece.The exact location remains unclear.

It has been called also Battle of Kastoria because the three Byzantine sources (Pachymeres, George Akropolites, Gregoras) informs us that the Epirotic camp was firstly attacked there[ in a location called Boril's Wood.

However, since the warfare includes also a siege of Prilep, it is justifiably called the Battle of Pelagonia.