Karamürsel Alp was a naval commander who rose to prominence during the founding era of the Ottoman Empire and gave his name to the district of Karamürsel on the coast of the Gulf of İzmit. He lived in the early 14th century and was among the first naval commanders of the state under Osman Gazi. Some historical accounts describe him as a devşirme of Macedonian origin, reflecting the early Ottoman Empire’s diversity in human resources.

Karamürsel Bey was appointed by Osman Gazi in 1323 following the conquest of the port of Kynoukhos (modern-day Karamürsel), which at the time was under Byzantine control. The incorporation of Kynoukhos into Ottoman territory enabled the state to gain both military and commercial control over the region and laid the groundwork for the establishment of the Ottoman Empire’s first shipyard.

This shipyard became one of the earliest institutional structures of Ottoman naval power. During this period, Karamürsel oversaw the construction of the empire’s first ships and led naval expeditions using galleys bearing his name—the Karamürsel Kadırgası.

The naval force under Karamürsel Bey’s command strengthened Ottoman presence not only around the Gulf of İzmit but also along the entire coast of the Sea of Marmara. The conquest of settlements in the areas of Hereke, Gebze, and Yalova exemplifies the strategic advances of this period. Maritime supply lines and military support played a decisive role in the Ottoman expansion toward the west.

There is no definitive information regarding the exact time or manner of Karamürsel Bey’s death, but some sources indicate that he was martyred in 1329 during a conflict with Byzantine forces. His tomb is located in a türbe bearing his name in the Karamürsel district of Kocaeli.

He is believed to have contributed significantly to the naval power that the Ottoman State developed in subsequent centuries through the infrastructure he established. His name was also permanently preserved as a geographical designation through the settlement he conquered.

The Karamürsel district of Kocaeli province contains numerous elements that preserve the memory of Karamürsel Bey. The Karamürsel Bey Monument, his türbe, and symbolic traces of the Karamürsel Shipyard define the historical identity of the region. The district’s social fabric and local governance continue to sustain Karamürsel’s historical legacy through educational, cultural, and tourism initiatives.

^{Karamürsel Bey Monument (}Türkiye Culture Portal⁾