>>1294482it's old fashioned, archaic by today's standards. that line is from a very old translation, from a very old book:
>Also in Early Modern English, to become (and some other intranstive verbs like to come and to go) used the auxiliary be rather than have for perfect aspect constructions. In current usage, to have is standard.>1965, The Decision to Drop the Bomb, PeriscopeFilm, spoken by Interviewee (J.R. Oppenheimer), the original text in Sanskrit and his own translation:>कालोऽस्मि लोकक्षयकृत्प्रवृद्धो / लोकान्समाहर्तुमिह प्रवृत्तः ।>kālo’smi lokakṣayakṛtpravṛddho / lokānsamāhartumiha pravṛttaḥ .>Now I am become Death, the destroyer of worlds 
