In 1817, Henri Beyle published his Histoire de la peinture en Italie and Rome, Naples et Florence (the first book written under his pen name Stendhal). These writings were different in nature and inspiration, but from both of them emerges a predilection for the painting of the Po valley region which was by no means straightforward or conventional. The present study, through a careful examination of Stendhal's main works, focuses on the ideas and opinions developed by the French writer concerning the two most eminent Emilian painters of the 17th century, Guido Reni and Guercino. Stendhal had the opportunity to admire and become familiar with many masterpieces by these famous artists, both in the halls of the Musée Napoléon in Paris and during his long stays in Italy (especially in Milan, Bologna and Rome), and therefore to record important reflections and considerations in his writings (including Promenades dans Rome of 1829).