Directors of the Leiden botanic garden Adriaan van Royen (1704–1779) and his nephew David van Royen (1727–1799) accumulated a large number of plant specimens in their herbarium collection. The “Van Royen herbarium” at Naturalis Biodiversity Center (Leiden, the Netherlands) holds 89 specimens currently attributed to the Prussian botanist Jacob Breyne (1637–1697). The identity, provenance and history of these Breyne specimens were never studied, although this collection may contain specimens missing from two book herbaria by Breyne (dated 1659 and 1673). Here, we reveal the species represented by the Breyne specimens in the Van Royen collection, as well as their origin and the information contained on their labels. A total of 75 species were identified in Breyne’s specimens, mostly collected in the surroundings of Montpellier (south-eastern France). Of the 89 specimens attributed to Breyne, 54 contain labels in his own handwriting, confirming they were collected (or at least owned) by him. The specimens are not derived from Breyne’s book herbaria also kept in the Leiden collection, as these contain mostly Polish plants. Breyne most likely did not collect these specimens himself, but received them from one or several of his correspondents with ties to Montpellier. It is not known how Breyne’s specimens ended up in the Van Royen herbarium (possibly through his son Johann Philipp), but they provide an insight in the flora of Mediterranean France in the 17th century, and reflect changes in nomenclature and the state of botanical science at that time.