Capitalisation of nouns in english in the 17th and 18th centuries

Not sure what your question is, but here is some information about it:

- It was introduced around 1750s but people already partially stopped using it around 1790s
-There were some specific rules for it, but there was some confusion about them and not everyone followed them
- it started with the capitalization of the main word in the sentence and then Capitalisation of all Substantives was introduced
-in German such a capitalization was introduced in 17th century too, and remains to this day

Question 3)

Edgar Guest was a 20th century POET.

I really hope that I helped! : )