Teaching materials generally included, and often did not exceed, a hornbook, primer, Psalter and Bible. A hornbook law is a basic, settled legal principle (see black letter law). The phrase is nearly synonymous with the phrase "hornbook law". From the first hornbook, the alphabet format cemented the learning progression from syllables to words. The hornbook, a form of ABC book, was common by Shakespeare's day. A hornbook is a book that serves as primer for study. John Wilson of Tarbolton of "Dr Hornbook" fame was her teacher for a brief period. "Address to the Deil" and "Death and Doctor Hornbook". Previously, a single-sided hornbook had been used for early literacy education. The hornbook originated in England as long ago as 1450, or earlier. The usual texts in the beginning were the Bible, a primer, and a hornbook.