Battle of Pelekanon
The Battle of Pelekanon (also known as the Latinized form Battle of Pelecanum ) took place on June 10th and 11th, 1329 between a Byzantine raiding party under Andronikos III. and an Ottoman army under Orhan I. instead. The Byzantine army was defeated, after which the Byzantine side made no further attempts to protect the cities of Asia Minor from the Ottomans.
When Andronikos ascended the throne in 1328, the Byzantine Empire's holdings in Asia Minor had shrunk to a few scattered outposts along the Aegean Sea and a small strip around Nicomedia . The capital Constantinople was only about 150 km away from the Turkish rule. Andronikos decided to free the cities of Nicomedia and Nikäa from the Turkish embrace.
Together with the Megas Domestikos Johannes Katakouzenos , Andronikos led an army of around 4,000 soldiers ( i.e. the entire Anatolian contingent of the empire) along the Marmara Sea towards Nicomedia. A Turkish army blocked their way near Pelekanon. Parts of the two armies became involved in fighting and the Turks were forced to retreat. Most of the Turkish army only retreated into the hills north of Pelekanon and Andronikos could not march on until the army was defeated. In further battles the emperor was slightly wounded. A rumor spread that the emperor was fatally wounded, causing panic. The Turks attacked the Byzantines again and caused them heavy losses until the Megas Domestikos was able to organize the retreat by sea to Constantinople.
The campaign to relieve the besieged Byzantine possessions was broken off. The Byzantines should never again attack Asian territory. The ancient cities of Nicomedia and Nicaea were not protected and soon fell to the Ottomans.
- W. Treadgold: A History of the Byzantine State and Society. 1997, p. 761.