Laudator Temporis Acti

E.R. Dodds, Select Passages Illustrating Neoplatonism (London: Society for Promoting Christian Knowledge, 1923), p. 8 (from the Introduction):

In 415 the amiable and brilliant Hypatia, head of the Neoplatonic school at Alexandria, was murdered by Christian monks. By this time, however, the disciples of Plotinus had succeeded in winning from the orthodox Academy the coveted chair of Plato at Athens; and it was in Plato's city that Greek thought made its last stand against the Church which it envisaged as "a fabulous and formless darkness mastering the loveliness of the world."<sup>2

2</sup> Eunapius, Vita Maximi.

Dodds' citation isn't quite accurate. Although I don't have access to Giuseppe Giangrande, ed., Eunapii Vitae Sophistarum (Rome: Istituto poligrafico dello stato, 1956), I think the quotation actually occurs in Eunapius' Life of Aedesius (not Maximus), in his Lives of the Sophists 6.9.17 (471 in the Didot pagination; tr. Wilmer Cave Wright, with her note):

Though he [Antoninus] himself still appeared to be human and he associated with human beings, he foretold to all his followers that after his death¹ the temple would cease to be, and even the great and holy temples of Serapis would pass into formless darkness and be transformed, and that a fabulous and unseemly gloom would hold sway over the fairest things on earth. To all these prophecies time bore witness, and in the end his prediction gained the force of an oracle.

¹ Antoninus died about 390; the Serapeum was destroyed in 391.

αὐτὸς μὲν οὖν ἔτι ἄνθρωπος εἶναι δοκῶν καὶ ἀνθρώποις ὁμιλῶν, πᾶσι τοῖς ὁμιληταῖς προὔλεγεν, ὡς μετ' ἐκεῖνον οὐκ ἔτι τὸ ἱερὸν ἔσοιτο, ἀλλὰ καὶ τὰ μεγάλα καὶ ἅγια τοῦ Σεράπιδος ἱερὰ πρὸς τὸ σκοτοειδὲς καὶ ἄμορφον χωρήσει καὶ μεταβληθήσεται, καὶ τὸ μυθῶδες καὶ ἀειδὲς σκότος τυραννήσει τὰ ἐπὶ γῆς κάλλιστα. ὁ δὲ χρόνος ἀπήλεγξεν ἅπαντα, καὶ τὸ πρᾶγμά γε εἰς χρησμοῦ συνετελέσθη βίαν.

Antoninus here = Antoninus 7 in Prosopography of the Later Roman Empire, Vol. I, p. 75.

For a commentary on this passage, see Matthias Becker, ed., Eunapios aus Sardes, Biographien über Philosophen und Sophisten. Einleitung, Übersetzung, Kommentar (Stuttgart: Franz Steiner Verlag, 2013), pp. 326-330.

As others have noted, the quotation as found in Dodds was taken up and slightly modified by W.B. Yeats in the second of his "Two Songs from a Play," line 5, Collected Poems, ed. Richard J. Finneran (New York: Palgrave Macmillan, 1989), pp. 213-214:

In pity for man's darkening thought
He walked that room and issued thence
In Galilean turbulence;
The Babylonian starlight brought
A fabulous, formless darkness in;        5
Odour of blood when Christ was slain
Made all Platonic tolerance vain
And vain all Doric discipline.

Everything that man esteems
Endures a moment or a day.        10
Love's pleasure drives his love away,
The painter's brush consumes his dreams;
The herald's cry, the soldier's tread
Exhaust his glory and his might:
Whatever flames upon the night
Man's own resinous heart has fed.