Proemio e carta al condestable de Portugal

The Proemio e carta al condestable de Portugal is a significant work by Iñigo López de Mendoza, the marquis de Santillana, written in 1449. It is considered the first example of formal literary criticism in Spanish. In this preface, Santillana outlines three distinct literary styles: high, for classical Greek and Latin works; middle, for formal vernacular writings; and low, for ballads and songs lacking formal structure.12

Santillana was a prominent Spanish poet, scholar, soldier, and statesman of the 15th century. He was instrumental in promoting the translation of classical works into Spanish and is credited with writing the first sonnets in the Spanish language, influenced by Petrarch. While his sonnets are admired, he is perhaps more celebrated for his serranillas (pastoral songs) and his preface, which laid the groundwork for literary history and criticism in Spain.21