This chapter examines the aftermath of Marcus Crassus’ defeat in Parthia in 53. The Parthian threat was real, as was the defence response, but there was no move to avenge Crassus in these years. Instead, Rome disowned Crassus’ aggressive campaign while embracing principles of ethical governance long advocated by Pompey and Cato. The blow to Rome’s military supremacy, combined with endemic misgovernment, created the threat of rebellion within Roman provinces; we therefore find Cicero, Gaius Cassius, Marcus Bibulus, and others striving not only to defend against Parthian attack but also to secure the loyalty of the allies by means of fair and upright governance. In this way, Crassus’ defeat provided the catalyst for an ongoing programme of provincial reform. Another product was the senatus consultum of 53, passed probably with Cato’s backing, which became the lex Pompeia de provinciis of 52 (the subject of chapter 7).