It's late for some personal reasons as well. Milton had been, as you know, anticipating writing this poem since he was at least nineteen years old.

也有一些个人原因，你们知道，弥尔顿至少在19岁的时候就想要写这样一首诗了。

耶鲁公开课 - 弥尔顿课程节选

Now we know that Milton was blind probably well before the time he began writing Paradise Lost, and therefore, of course, he was then unable to read.

现在我们知道弥尔顿很可能失明了,这早于他开始写《失乐园》的时间，因此，他不能通过眼睛阅读。

耶鲁公开课 - 弥尔顿课程节选