The article examines the development of the diplomatic function of Spanish painting in the 16th and 17th centuries, using the iconography of Spanish infants’ portraits as an example. In Spain, the social status of painters was lower than in Italy. Spanish masters had to pay a tax on their craft – alcabala – against which they actively fought, seeking recognition of painting as a Liberal Art. Gradually, they succeed. The transformations in the role of infants’ court portraits were related with this process. Initially, their main function was memorial, with the primary recipients being relatives of the royal family. Over time, the memorial function receded, and the representative function became more prominent: the portraits began to depict infantes and princes on the international stage, contributing to the country’s prestige and serving matrimonial purposes. By the 17th century, with their widespread presence on the European stage, Spanish paintings confirmed their high status as Liberal Art. The authors employ culturological, iconographic, iconological, artistic, and stylistic methods to analyze the material.