This chapter discusses the emergence of the rescript system – a paradigm in which emperors used correspondence to settle legal questions – over the second century CE. This paradigm is most closely linked with the emperor Hadrian, and I consider three major legal innovations from Hadrian’s reign: Hadrian replacing the annually renewed Praetor’s Edict with a Perpetual Edict under more formal imperial control, Hadrian sunsetting the “right of response” which had formerly been given to individual jurists, and Hadrian’s vast expansion of the imperial bureaucracy and correspondence system. I then consider how imperial legal replies, or “rescripts,” could represent imperial sovereignty in a variety of different modes, from the collaborative and deliberative style of the Diui Fratres to the more bureaucratic and concise mode visible in documents like P.Col.123.