Around the year 1220, the then reigning lord of the region erected a fortified tower in order to protect the imperial highway at the toll station in Horrenberg. For the location of the fort, they chose a hill next to the highway which loomed a swampy low-lying section of the Leimbach. "Horrenberg" comes from HOR- swamp or mud and BERG mountain or hill. Around the castle a small village developed over time. The first noble recorded in association with Horrenberg is Dieter von Horrenberg in 1238. He was most likely named after the new castle. Before 1272, bishop Henry of Speyer took over the upper Bruhrain to which the village Horrenberg and castle belonged. This purchase related document is the first definitive mention of Horrenberg. Older documents cannot be fully relied upon because of the similar way Castle Hornberg on the Neckar was written at that time. In 1366 emperor Charles IV confirmed the right of bishop Lamprecht of Speyer to collect the toll income of Horrenberg.