The article discusses two issues of 18th century performance practice concerning the french horn. The first part reveals that there was a common practice of hiring four horns, two to play the higher keys and two to play the lower, with the central key of F as the pivot point. The second part addresses the alto-basso controversy, with evidence for the traditional performance of horns in B-flat in the alto range, with the basso range for the key a relative latecomer to music. The further issue regarding C major, however, is more ambiguous, given contrary documentation.