This thesis examines the allegiance of Scottish bishops between 1332, when Edward Balliol invaded Scotland, and 1357, when the Treaty of Berwick established a fragile peace between England and Scotland. This period witnessed the so-called ‘Second War of Scottish Independence’, in which David II fought Balliol and Edward III of England for the Scottish throne. Until now, no study of the ‘Second War’ has examined bishops’ allegiance, nor has any study of the Wars of Independence (1296-1357) supplied a rigorous framework to analyse prelates’ bonds with kings. The thesis addresses this lacuna and seeks to establish a new way of thinking about Scottish allegiance, the hierarchical bond between king and subject. It argues that allegiance was connected but distinct from Scottish regnal identity, by using governmental, ecclesiastical, and chronicle evidence. Chapter one analyses existing scholarship on medieval allegiance and highlights the problematic terminology historians have used to describe allegiance. Chapters two and three establish a new way of approaching allegiance by examining medieval theological and legal conceptions of bishops’ relationships with the king. This is achieved by, first, demonstrating bishops’ power when legitimising royal authority during royal inaugurations and, second, by considering bishops’ legal obligations as subjects and potentates. Chapter four applies these findings to the allegiance of bishops in the conflict between 1332 and 1357. This final chapter demonstrates that bishops’ loyalties were not binary and static but flexible and fluctuating. While some bishops were short-term affiliates of Balliol, many bishops provided continuous support to David throughout the 1330s and 1340s. Therefore, bishops played a crucial role in defending Scotland’s independence. Overall, the thesis demonstrates that allegiance cannot be described merely as a binary between loyalty and disloyalty but must be viewed as a spectrum of behaviour between pro-active service and the fulfilment of legal obligations.