What are some ways of recalling or contextualizing dense material? I have trouble with dates, especially the whole thing with written centuries (for instance, writing 'fifteenth century' instead of the 1400's).
Don't forget that "the 1400s" correctly refers to the first decade of the fifteenth century, not the whole century.
People increasingly use it to mean the whole century, which I think is an Americanism that (like so many others) is spreading, but that is not right. After all, "the 1900s" has always meant the Edwardian era, not the entire twentieth century.