Pereyaslavets (East Slavic: Переяславец) or Preslavets (Bulgarian: Преславец) was a trade city located near mouths of the Danube.
Several theories exist regarding the exact location of the city: either at Preslav or in its vicinity in Bulgaria, or at Isaccea, Nufăru, Murighiol or Jurilovca in Romania.
A thriving trade centre of the First Bulgarian Empire, it was captured by Prince Svyatoslav of Kievan Rus in 968 (See Sviatoslav's invasion of Bulgaria).
Upon his return to Bulgaria, Svyatoslav promptly suppressed the rebellion and, to the chagrin of his mother and relatives, transferred the capital from Kiev to Pereyaslavets.
According to the Primary Chronicle (its record for year 969), Svyatoslav explained to his courtiers that it was to Pereyaslavets, the centre of his lands, that "all the riches would flow: gold, silks, wine, and various fruits from Greece, silver and horses from Hungary and Bohemia, and from Ruthenia furs, wax, honey, and ancient laws".