This thesis examines the influence of the two major priestly colleges in late republican Rome, the pontificate and the augurate, and aims to explain why membership was valued so highly by members of the Roman élite. Chapter one discusses the exclusive selection process for the priests and the aristocratic prerequisites for membership. In light of the changes to the way priests were selected, resulting from the lex Domitia in 104 BC, this chapter explores the extent to which these offices can be seen as either inherited family rights or political prizes granted through the support of powerful figures like Sulla or Caesar. The second and third chapters consider whether the pontiffs and augurs respectively had significant constitutional ;;hard powers’, comparing their influence to the central religious authority of magistrates and the senate. The collective influence of the pontifical college is examined in the second chapter by assessing their involvement in the decision to reverse the dedication of a shrine on the site of Cicero’s house in 57 BC. This discussion will also analyse the influence of the young individual pontiff, L. Pinarius Natta, who assisted the tribune Clodius at the dedication ceremony in 58 BC. In the third chapter, the individual powers of the augurs are compared to the imperium of magistrates by analysing seven cases of obnuntiatio between 59 and 44 BC, and examining Mark Antony’s use of augural obstruction in his capacity as augur in 44 BC. The chapter also discusses the collective influence of the augurs through the promulgation of decrees and their role during the religious controversies of Caesar’s first consulship in 59 BC. The final chapter suggests that these priesthoods were a means of social advancement, offering young political hopefuls a productive entrée into élite society. This discussion utilises prosopographical data to analyse the extent to which becoming a pontiff or augur at the start of a political career increased an incumbents chances of reaching the consulship. Following this the chapter considers how these positions provided networking opportunities which could translate into political support, facilitating what is termed as ;;soft power;;.