This article aims to analyse the finances of the Coimbra city council from 1557 to 1836. Our objective is to examine the causes of long-term changes in municipal revenue and expenditure, particularly during the extended period of decline that occurred between the mid-17th century and the late 18th century. This study will focus on the composition of revenue and expenditure, as well as on revenue collection mechanisms. We aim to present the empirical data on the revenue and expenditure components that allow us to understand the changes that took place. Finally, we hope to be able to explain the causes that led to significant variations in revenue and expenditure in a dialogue with existing literature. The primary sources used correspond to municipal revenue and expenditure books, supplemented by other sources such as legislation, correspondence and auction books.