The Martinsburg was built at the end of the 13th century as a base for exercising the Mainz customs rights. Since 1292, the Archbishopric and Electorate of Mainz had secured shares in the Boppard Imperial customs with the permission of King Adolf of Nassau. Since the Electorate's castle of Lahneck rose somewhat distant from the Rhine on a hill, a solid building was erected directly on the Rhine to secure the collection of the Rhine customs. Probably, a fortified structure had already existed at this site to monitor shipping as early as the mid-13th century, which was mentioned in a document from 1244.

The oldest parts of the castle consist of a rectangular residential tower equipped with two corner towers, as well as the foundations of the hexagonal main tower in the south of the complex. The 28-meter-high keep that rises at this location today was built around 1400 and features an adjoining stair and latrine tower.

In connection with the construction of the city wall of Oberlahnstein after 1324, the Martinsburg was also expanded. It formed the southwestern corner point of the city fortifications. Towards the city, the lowland castle was secured with a moat and a solid gate, at which a portico is still visible today. From such protruding features above the castle gate, attackers could be doused with hot pitch or oil. The fortifications towards the city were necessary, as it could be captured by enemies, leaving the castle as the last refuge for the Mainz officials. However, a rising of the townspeople against their episcopal-electoral lords was also not entirely out of the question. As the town castle of the economically booming Oberlahnstein, it housed the customs clerk and customs personnel, gatekeepers, and tower watchers, as well as additional auxiliary staff.

The water castle was never destroyed, but it was altered by additions and renovations until the end of its affiliation with Kurmainz in 1803. Thus, in the 14th century, the northwest wing was added, followed by the present southeast wing in 1497. Between 1719 and 1721, the then existing gap on the Rhine side between the medieval residential tower and the keep was closed with a three-story central building in the style of the Baroque.

As an occasional secondary residence of the Mainz Electors, Schloss Martinsburg could far surpass the importance of the castle Lahneck since the end of the Middle Ages.