Altes Schloss, Neckarbischofsheim, Renaissance château in Neckarbischofsheim, Germany

Altes Schloss, also called Steinernes Haus, is the oldest surviving building in Neckarbischofsheim. Its free-standing core is what remains of a castle complex: a stair turret with the alliance coat of arms of Philipp von Helmstatt and Margarethe von Neipperg, and a Rittersaal with a decorated oriel. A side wing was added from 1546; the fourth storey burned down in 1859.

A castle was first mentioned in 1274 and is the oldest surviving building in Neckarbischofsheim. In 1378 Weiprecht I von Helmstatt became sole owner of castle and village. Johann von Helmstatt had the core building extended from 1546, adding a side wing, a stair tower and a decorated oriel on the Rittersaal. A fourth storey burned down in 1859, and the town bought the castle in 1975.

The building is also called Steinernes Haus, and the Helmstatt family held it until the male line died out in 1952. The town bought it in 1975 and restored it. The Rittersaal now serves as a wedding room, and the other rooms hold a local history museum.

The building is owned by the municipality of Neckarbischofsheim, which acquired it in 1975 and renovated it. The Rittersaal now serves as a wedding room, and the remaining rooms house a local history museum. In the Schlosspark stands a Renaissance gateway of 1590, attributed to the sculptors Adam Wagner or Jakob Müller of Heilbronn.

The oldest surviving part is a section of wall behind the stair tower, likely from the high medieval residential tower. Dendrochronological dating of timbers places the interior rebuild around 1368, so substantial 14th-century fabric survives inside.