A son of Iphiclus and Astyoche, and accordingly a brother of Podarces, belonged to Phylace in Thessaly, whence he is called Phulakios (Lucian, Dial. Mort. 23. 1 ; Hom. Il. ii. 705; Eustath. ad Hom. p. 323), though this name may also be traced to his being a grandson of the Aeolid Phylacus. He led the warriors of several Thessalian places against Troy, and was the first of all the Greeks that was killed by the Trojans, for he was the first who leaped from the ships upon the Trojan coast (Hom. Il. ii. 695, &c. xiii. 681, xv. 705; Philostr. Her. ii. 15). According to the common tradition Protesilaus was slain by Hector (Lucian, l. c. ; Tzetz. ad Lyc. 245, 528, 530; Hygin. Fab. 103; Ov. Met. xii. 67), but, according to others, he fell by the hands of Achates (Eustath. ad Hom. p. 326), or Aeneas (Dict. Cret. ii. 11), or of Euphorbos (Eustath. l. c. p. 325). Protesilaus is most celebrated in ancient story for the strong affection and fidelity existing between him and his wife Laodameia, the daughter of Acastus. When she heard of the death of her husband, she prayed to the infernal gods to be allowed to converse with him only for the space of three hours. The prayer being granted, Hermes conducted Protesilaus for a few hours to the upper world, and when Protesilaus died a second time, Laodameia expired with him (Hygin. Fab. 108 ; Eustath. p. 325). This story, from which the account of Lucian differs only slightly, has been variously modified by the poets, for, according to some, Laodameia, after the second death of her husband, made an image of him, which she worshipped, and when her father Acastus ordered her to burn it, she threw herself with the image into the flames (Hygin. Fab. 104). According to others, Protesilaus, on returning from the lower world, found his wife embracing his image, and when he died the second time, he begged of her not to follow too late, whereupon she killed herself with a sword. Others again relate that Laodameia, being compelled by her father to marry another man, spent her nights with the image of Protesilaus (Eustath. l. c.); but Conon (Narrat. 13), lastly, has quite a different tradition, for according to him, Protesilaus, after the Trojan war, took with him Aethylla, a sister of Priam, who was his prisoner. When, on his homeward voyage, he landed on the Macedonian peninsula of Pallene, between Mende and Scione, and had gone some distance from the coast, to fetch water, Aethylla prevailed upon the other women to set fire to the ships. Protesilaus, accordingly, was obliged to remain there, and built the town of Scione.
His tomb was shown near Eleus, in the Thracian Chersonesus (Strab. xiii. p. 595; Paus. i. 34. § 2 ; Tzetz. ad Lyc. 532). There was a belief that nymphs had planted elm-trees around his grave, and that those of their branches which grew on the Trojan side were sooner green than the others, but that at the same time the foliage faded and died earlier (Philostr. Her. ii. 1); or it was said that the trees, when they had grown so high as to see Troy, died away, and that fresh shoots then sprang from their roots (Plin. H. N. xvi. 99; Anthol. Palat. vii. 141, 385). A magnificent temple was erected to Protesilaus at Eleus, and a sanctuary, at which funeral games were celebrated, existed in Phylace (Herod. vii. 33, 116, 120; Paus. iii. 4. § 5; Pind. Isthnm. i. 83, with the Schol.). Protesilaus himself was represented in the Lesche at Delphi. (Paus. x. 30. § 1.)