Synesius (/sɪˈniːsiəs/; Greek: Συνέσιος; c. 373 – c. 414), a Greek bishop of Ptolemais in the Libyan Pentapolis after 410, was born of wealthy parents, who claimed descent from Spartan kings, at Balagrae (Bayda now) near Cyrene between 370 and 375.
His many-sided activity, as shown especially in his letters, and his loosely mediating position between Neoplatonism and Christianity, make him a subject of fascinating interest. His scientific interests are attested by his letter to Hypatia, in which occurs the earliest known reference to a hydrometer, and by a work on alchemy in the form of a commentary on pseudo-Democritus.








