Abstract: The present invention relates to novel terpene synthases. The terpene synthases are capable of synthesising mono-, bi- and/or tri-cyclic sesquiterpenes having a C2-C7 or a C3-C7 bond, starting from an acyclic pyrophosphate terpene precursor, farnesyl-pyrophosphate. Accordingly, for the first time, sesquiterpene synthases catalyzing the cyclisation to the santalene and bergamotene carbon skeleton are disclosed. The present invention further relates to nucleic acid sequences encoding the sesquiterpene synthases and to methods for making terpenoids.