Drawing on an extensive range of textual and visual sources, the thesis argues that pilgrimage to Santiago de Compostela triggered the development of an extensive money economy between the late eleventh and early thirteenth centuries that led to a profound socio-economic transformation of communities along the pilgrim roads. Part I explores the origins of the pilgrimage’s devotional infrastructure, the evolution of pilgrim towns and markets, and the role of money and financial services in increasing the popularity of the pilgrimage. It further shows how iconography of coins was used to promote the cult of St James and the political agendas of Compostela’s cathedral chapter and the Leonese monarchy. Part II pivots to money as a social disruptor and agent of change. It explores the underlying causes and implications of urban revolts that pitted ambitious ecclesiastical lords against the rising class of merchants and craftsmen. It then unravels moral challenges related to the sin of avarice and how money was remade in a religious context to facilitate spiritual salvation. Finally, the thesis argues the money economy triggered a social reordering and that a tacit moral accommodation was reached between the Church and merchant class in order to facilitate the act of pilgrimage.