Charles D. Morris, Commentary on Thucydides Book 1

αἰτίαι: as the following exposition shows, the pl. refers only to the affair of Potidaea in its two aspects, as affecting the Athenians and the Peloponnesians; and προσεγεγένηντο of the best Mss. is to be preferred to προεγεγένηντο, as this clause stands in close connexion with c. 55. § 2, where, after the narration of the affair of Corcyra, we read, αἰτία αὕτη (the sing., because one only relation is regarded) πρώτη ἐγένετο τοῖς Κορινθίοις ἐς τοὺς Ἀθηναίους, to which this passage adds a second αἰτία. Ullrich, Beitr. zur Krit., I. p. 27 ff. As Aristeus had brought other Peloponnesians with him (c. 60. 5; 62. 2) to the support of Potidaea, the hostile feeling extended itself beyond the Corinthians, who were first affected by it. This accounts for the mention of Πελοποννησίοις in 1; and the expression αἰτίαι has the general meaning of ground of complaint (in c. 146. 1, connected with διαφοραί), and without the addition of τοῦ πολέμου, as in c. 55. 13. So αἰτίαι μέν is opposed to οὐ μέντοι κτἑ. in 8, i.e. to the actual outbreak of the war.

ἀπὸ τοῦ προφανοῦς: see on c. 34. 10.

ξυνερρώγει: from ξυρρηγνύναι, here only in Attic writers, but often used by Appian., Dio Cass., Plut. In viii.96.7, we have the related fut. ξυρράξουσι（ῥάσσω).

ἰδίᾳ: on their own account, without the instigation of others. Here ἔπραξαν must be rendered as plpf.; cf. c. 128. 16, 17.

NEGOTIATIONS AND RESOLUTIONS IN THE LACEDAEMONIAN POPULAR ASSEMBLY. Chaps. 67-87.