2 Answers

One helpful resource would be a collegiate level dictionary,  that would give you a more indepth understanding of the usage of certain words during that time period. Throughout the years,  words have evolved to have various specific  meanings during different time periods. Usually the circa of usage and meaning will appear near the top of the definition.

If you can find a book in the library that is focused on the origin of words, that would be helpful also, as they often explain a words evolution. The study of word origins and meaning is known as Etymology.

That sounds as though it falls within the study of what is called English litrature. Try googling poem meanings to see what comes up. But, don't always accept one person's opinion as being 100% correct. Research it yourself too! It's a good opportunity to expand your understanding of the language.