incipio

Incipio, incipere, incepi, inceptum is third conjugation -io, in- plus capio, "take", so literally "take hold of". Watch the vowel: the present stem has i (incipit) and the perfect has e (incepit), so a single letter separates "he begins" from "he began".

It takes a complementary infinitive (incipit scribere) or a direct object (bellum incipere). The thing to know is its relationship with coepi, which is defective and has only perfect forms: classical Latin habitually uses incipio for the present system and coepi for the perfect, so the two verbs share one paradigm between them. If you want "he began" in good prose, coepit is at least as likely as incepit. English inception, incipient and inchoate-adjacent vocabulary come from here; the medieval university word inceptor meant a man beginning as a master, not a beginner.