Geoffrey of Aulnay was Baron of Arcadia in the Principality of Achaea in the late 13th century.
[3] In 1292 or 1293, Geoffrey went on a diplomatic mission to the Byzantine court in Constantinople along with John Chauderon, in order to obtain the recovery of the fortress of Kalamata, which had shortly before been seized by local Slavs and handed over to the Byzantine governor of Mystras.
The embassy succeeded in obtaining a verbal promise only thanks to the intercession of the Angevin ambassador to Constantinople; the Byzantine emperor even insisted that the castle be handed over to Geoffrey, rather than the Prince of Achaea.
At the same time, the emperor also sent orders to his local governor to refuse to hand the castle over.
In the event, Kalamata was surrendered to the Achaeans due to the intervention of a local Greek magnate, Sgouromallis.