The first evidence of the construction of the residence in Mosbach can be traced back to when the town's fortification was erected by Count Palatine Otto I early in the fourteenth century.
The context of the castle's first reigning occupant helps amplify its importance today and at the time it was first built.
Count Palatine Otto I, who was born in Mosbach in 1390 and then chose to have his residence there as the heir to the Palatinate Electorate in 1410, and his son Otto II, had the Castle expanded considerably after 1430, although the work done on the building was not intended to exude grandness.
The most influential period for the Castle came in 1427 when, alongside the duties involved in administering the Palatinate-Mosbach, Otto I assumed the guardianship of his nephew Louis IV (Ludwig IV) and held the regency by default while his brother Louis III was too weakened and ill to rule upon his return from a crusade to Jerusalem in 1427.
The castle's present-day appearance largely stems from renovation carried out in 1898, including bay windows, half-timbered walls and transverse gables.