Time.—The time denoted by the participle is only relative to that of the governing verb, and is to be inferred from the context. Each participial form in itself expresses only stage of action ( cross1850).
ἀκούσα_σι τοῖς στρατηγοῖς ταῦτα ἔδοξε τὸ στράτευμα συναγαγεῖν on hearing this it seemed best to the generals to collect the troops
a. Several temporal participles have an adverbial force: ἀρχόμενος
ἅπερ καὶ ἀρχόμενος εἶπον
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].