For classic books like those you mentioned, Project Gutenberg has text versions along with pdfs/epubs/etc.
For instance, Discourses on Livy:
https://www.gutenberg.org/cache/epub/10827/pg10827-images.ht...
Even better is when Standard Ebooks publishes a version: https://standardebooks.org/ebooks/niccolo-machiavelli/discou...