Diego Velázquez notable work Las Meninas
Las Meninas
One of the infantas, Margaret Theresa, the eldest daughter of the new queen, appears to be the subject of Las Meninas (1656, English: The Maids of Honour), Velázquez's magnum opus. 
Created four years before his death, it serves as an outstanding example of European baroque art. Luca Giordano, a contemporary Italian painter, referred to it as the "theology of painting", and in the eighteenth century the Englishman Thomas Lawrence cited it as the "philosophy of art". However, it is unclear as to who or what is the true subject of the picture. Is it the royal daughter, or perhaps the painter himself? The king and queen are seen reflected in a mirror on the back wall, but the source of the reflection is a mystery: are the royal pair standing in the viewer's space, or does the mirror reflect the painting on which Velázquez is working? Dale Brown says Velázquez may have conceived the faded image of the king and queen on the back wall as a foreshadowing of the fall of the Spanish Empire that was to gain momentum following Philip's death.
In the 1966 book Les Mots et Les Choses (The Order of Things), philosopher Michel Foucault devotes the opening chapter to a detailed analysis of Las Meninas. He describes the ways in which the painting problematizes issues of representation through its use of mirrors, screens, and the subsequent oscillations that occur between the image's interior, surface, and exterior.It is said the king painted the honorary Cross of Saint James of the Order of Santiago on the breast of the painter as it appears today on the canvas. However, Velázquez did not receive this honor of knighthood until three years after execution of this painting. Even the King of Spain could not make his favorite court painter a belted knight without the consent of the commission established to inquire into the purity of his lineage. The aim of these inquiries would be to prevent the appointment to positions of anyone found to have even a taint of heresy in their lineage—that is, a trace of Jewish or Moorish blood or contamination by trade or commerce in either side of the family for many generations. The records of this commission have been found among the archives of the Order of Santiago. Velázquez was awarded the honor in 1659. His occupation as plebeian and tradesman was justified because, as painter to the king, he was evidently not involved in the practice of "selling" pictures.
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