We examined the seismicity of the region of the Sea of Marmara in northwest Turkey over the last 2000 yr using the historical record of the region. We found no evidence for truly large earthquakes of a size comparable to those in the North Anatolian Fault zone in the Marmara Basin. Events are smaller in keeping with the known fault segmentation of the Basin. Over the last 2000 yr seismic moment release accounted for the known right-lateral shear velocity across the Marmara region observed by Global Positioning System measurements. Its average rate is relatively constant and varies between 1.6 and 2.4 cm/yr. The long-term seismicity in the Marmara Sea region shows that large earthquakes are less frequent than predicted from the 100-yr-long instrumental period.