μεγάλα ὠφελήσεσθε πρὸς ἱστορίαν τῶν κοινῶν → that will be of great benefit to you in order to understand public affairs
crase att. et poét. p. τοῦ ἐμοῦ.
τοὐμοῦ: in crasi = τοῦ ἐμοῦ.