In medieval England, common law descended from writs issued by the royal chancery. These writs were compiled in a volume referred to as the Registrum Brevium (Register of Writs), the earliest surviving manuscript of which exists from 1227. These texts of writs was continually modified and updated, and the Registrum Brevium came to be one of the most common kind of legal manuscript in Medieval England. MS 158 is a pocket-sized and very incomplete version of the 'Register of Writs' text.

The text begins on f. 1r, with the line Rex G.vel ballivis G. de M. Salutem. This first writ is entitled De moderatamina Capienda. The final line of text for a writ called De Reddissimis on f. 68v, reads: illius reddissemine (?) sustinuit per sacram[entum].

Fairly written, with red and blue filigree initials.