ἦρχα

From LSJ

ταῦτα δηλώσω αὐτός τε νοσήσας καὶ αὐτὸς ἰδὼν ἄλλους πάσχοντας → I shall describe those symptoms, since I myself had the disease and witnessed as well what others were suffering

Source

French (Bailly abrégé)

v. ἄρχω.

Russian (Dvoretsky)

ἦρχα: pf. к ἄρχω.