History of English grammars
The first English grammar, Pamphlet for Grammar by William Bullokar, written with the ostensible goal of demonstrating that English was just as rule-based as Latin, was published in 1586. Bullokar’s grammar was faithfully modeled on William Lily’s Latin grammar, Rudimenta Grammatices (1534), which was being used in schools in England at that time, having been “prescribed” for them in 1542 by Henry VIII. Although Bullokar wrote his grammar in English and used a “reformed spelling system” of his own invention, many English grammars, for much of the century after Bullokar’s effort, were written in Latin, especially by authors who were aiming to be scholarly. John Wallis’s Grammatica Linguæ Anglicanæ (1685) was the last English grammar written in Latin.
Even as late as the early 19th century, Lindley Murray, the author of one of the most widely used grammars of the day, was having to cite “grammatical authorities” to bolster the claim that grammatical cases in English are different from those in Ancient Greek or Latin.