Bishop of Ptolomais, neo-Platonist, date of birth uncertain; d. about 414. He was a younger son of an ancient family of Cyrene which traced its descent from the Hieracleidæ, the mythical founders of the city. Synesius pursued his higher studies at Alexandria, where he became a devoted disciple of the famous Hypatia, to whom several of his letters are addressed and for whom he entertained a life-long devotion. After serving some time in the army he settled in his native land, "studying philosophy, mathematics, astronomy, everything; farming, hunting, having many a brush with hordes of pilfering Libyans; and every now and then upholding the cause of some one who had undeservedly fallen into difficulties". This kind of life, in every way suited to his tastes and disposition, was interrupted by a mission to Constantinople, the object of which was to present a gold crown to the new emperor, Arcadius, and obtain alleviation of the burden of taxation. Nearly three years he waited for an audience. The all-powerful Eutropius who sold the provinces to the highest bidder was not the man to allow the emperor to be troubled with complaints. Finally, Synesius obtained an audience and delivered his famous oration "On Kingship". He left Constantinople in 400. According to some authorities before, and according to others after, the mission to Constantinople, Synesius visited Athens. He had described the visit in two letters [54 and 135] to his brother, Euoptius. His reason for undertaking the voyage was, he jestingly said, that "a number of people, priests and private persons, had had revelations in dreams that, unless he did so, some great evil would befall him. Then he would escape the present evils and would no longer have to revere people who had been to Athens and regarded themselves as demigods, and those who had not as demidonkeys or mules." Athens was a disappointment. Like a beast that had been sacrificed, only the hide remained. At Alexandria, Synesius married a Christian by whom he had several children. During this period he did most of his literary work and carried on a large correspondence with his friends. Owing to the incapacity and cowardice of the military authorities, the desultory raids of the barbarians assumed almost the proportions of regular warfare. Synesius took a leading part in organizing defensive measures, levying volunteers, procuring arms, etc.

In 409 Synesius was elected Metropolitan of Ptolemais. The bishop-elect unbosomed himself in a letter [Ep. cv] to Euoptius. The duties of a bishop were uncongenial to him, fond as he was of his amusements as well as of religious study. He could not forsake the wife given him by "God, the law and the sacred hand of Theophilus". His amusements might go, much as he would hate to see his "darling dogs no longer allowed to hunt". Still, "if it is God's will, I will submit". But there was a worse obstacle, "Philosophy is opposed to the opinions of the vulgar. I certainly shall not admit that the soul is posterior to the body … that the world and all its parts shall perish together. The resurrection … I consider something sacred and ineffable and am far from sharing the ideas of the multitude". He could keep silence but not "pretend to hold opinions which he did not hold". Theophilus, he said, must know everything and decide. Seven months elapsed between the writing of this letter and Synesius's consecration. That Synesius should yield is hardly surprising. His dogmatic perceptions were not keen enough to make him realize the falseness of his position as a bishop. Theophilus, the persecutor of the Origenists, is the difficulty. Perhaps, like many masterful men, he could put the telescope to his blind eye and refuse to see what he did not wish to see. Perhaps the negations in Synesius's letter were not his last word with regard to doctrinal questions. Baronius held that Synesius defamed himself to escape the episcopate, and this was also the opinion of Jeremy Taylor, "for all this Theophilus, Bishop of Alexandria, consecrated him, as knowing all this to be but stratagem and the arts of an odd fantastic humility" [Ductor dubitantium, iii, 2]. The "fantastic humility" solution of the problem has found very few supporters. As a bishop, Synesius devoted himself to the multiform duties of this office, without, however, concealing how uncongenial such a press of business was to him. We find him first warning and then excommunicating a bloodthirsty governor, denouncing the Eunomians, superintending the elections of bishops, etc. His latter days were embittered by the death of his three sons and the ruin of his country by the barbarians. His last letter was to Hypatia. She had been to him, "a mother, a sister, and a teacher". In his last hymn he recommends himself to Christ. It is a prayer that "his sins may be forgiven and that he may behold the glory of the Saviour".

The following are his writings: "De Providentia", first part composed while in Constantinople, second part after return to Cyrene; a political pamphlet in which Gainas and Aurelian figure as Typhon and Osiris; "De regno", in which an ideal Roman emperor is presented in an oration, delivered before Arcadius; "De dono astrolabii", a treatise accompanying the gift of a planisphere to one Paconius at Constantinople. The following were written between 400 and 409: the "Cynogetics" (not extant), a treatise on the breeding of dogs; "De insomniis", a curious treatise on dreams. Divination, according to Synesius, following Plotinus, was possible because of the unity of nature. All parts of the universe are in sympathy, so in each thing there are indications of other things. "Dion", a vindication of his manner of life against stern asceticism; "Calvitii Encomium", a facetious eulogy on baldness by a man who suffered form that complaint. The following belong to 409-14: two fragments of homilies; "Constitutio sive elogium Anysii" (Anysius was a general who had been successful against the barbarians); "Catastasis", describing the ruin of Pentapolis. There are one hundred and fifty-five epistles and ten hymns written at different periods of his life, the latter valuable because of the light which they throw on his religious and philosophical views, the former, the most precious of his writings, because of the light they throw on the writer's personality, and the picture which they give of the age in which he lived.

The only complete edition of Synesius's writings is that published by P ETAVIUS (Paris, 1612); the fourth edition (1640) is the best; K RABINGER (1825-35) published the De regno, Calvitii, Encomium, and De providentia, with German translations and the first volume of a complete edition, Synesii opera omnia. I: Orationes et homiliarum fragmenta (Landshut, 1850). This volume contains the greater works but not the hymns or epistles. A new edition of the Hymns was brought out by B OISSONADE, Sylloge pietarum græc., XV (Paris, 1825); by C HRIST AND P ARANIKAS in Anthologia græca carminum christianorum (Leipzig, 1871). There is a French translation of the Epistles by L APATZ (Paris, 1870), very useful but not always trustworthy. See also V OLKMANN, Synesius von Cyrene (Berlin, 1869); C LAUSEN, De Synesio (Copenhagen, 1831); H ALCOMB, Dict. Christ. Biog.; G ARDNER, Synesius of Cyrene (London, 1886); C RAWFORD, Synesios, the Hellene (London, 1901); K RAUS, Studien über Synesios von Cyrene in Theol. Quartalschr. (Tübingen, 1865-66). For the religious views of Synesius when he was elected bishop see also H OLSTENIUS, Dissertatio de Synesio et Fuga Episcopatus, which will be found in R EADING's edition of Evagrius and Theodoret (Cambridge, 1720). Holstenius's view is opposed to that of Baronius.

F.J. B ACCHUS