It also said he only wrote hundreds of lines in 35 years. So maybe one line a month. Either he's a wizard that spins gold from straw or "mastered" is being used

It also said he only wrote hundreds of lines in 35 years. So maybe one line a month. Either he's a wizard that spins gold from straw or "mastered" is being used ironically. Given that he could be replaced by two juniors I'll assume the latter.