John Wallis published his Grammatica Linguae Anglicanae in 1653, an early grammar in Latin. Follow this link to Early English Books Online, and while you browse through its pages (whether or not you can read Latin) find your way to the discussion of the correct usage of "shall" and "will" on pages 94-95.
William Bullokar's Short Introduction or Guiding to Print, Write, and Reade Inglish Speech (1580) was part of a larger project, never realized, to publish a set of reference works including a dictionary and grammar. Examine the chart near the beginning which gives a modified alphabet for all English phonemes. Then, after browsing through more of its pages, written in his new orthography, go to the end, where you'll find a rhyme royal stanza that begins, "O England that of nations may'st rejoice/ most for God's gifts: with wealth and quiet ease." Notice what words rime with "ease." At the very end, with"God save our Queen Elizabeth," there is something unusual signalled by Bullokar's spelling system in the pronunciation of her name. What is it?
Bullokar also published a Pamphlet for Grammar (1586). Make notes about what it specifies for personal pronouns (pp. 20-21), especially the genitive of "it" and the use of "thou/thee" versus "you." Does he use "ye"? (To make sense of his spelling you need to refer to his Short Introduction, above.) What does he say about the distinction between "shall" and "will" (p. 33)?
Jonathan Swift's Proposal for Correcting, Ascertaining and Improving the English Language (1712) is not a grammar but rather a proposal for establishing a body to regulate the language, written in Swift's acerbic, muscular prose. Read it, and make notes about what it reveals about his view of language change and about the English language in general.