In 1878, Van Gogh already had three failed careers under his belt, as an art dealer, a teacher and a bookseller.
In the years 1878-80, he subsequently abandoned his theology studies before even attending a lesson, was rejected for a course of training to become an evangelist in Brussels, and his appointment as a lay preacher (a position that required no official training) wasn’t even renewed.
Vincent was gripped by a severe depression for nearly a year and was thrown completely upon his own resources. He eventually decided to take Theo’s advice and become an artist.
He’d always enjoyed drawing and liked art. But this was still a bit of a stab in the dark, as Vincent was certainly not a natural talent.