Marie van Goethem
Between 1878 and 1881, Degas drew, painted and sculpted Marie in artworks including "Dancer with Fan", "Dancing Lesson", "Dancer Resting", numerous preparatory sketches, and most famously in "Little Dancer of Fourteen Years". He frequently attended ballet performances at the Paris Opera and often observed classes at the dance school. By posing for Degas, Marie likely earned five to six francs per four-hour sitting.
Edgar Degas
Both regarded themselves as figure painters, and the art historian George Shackelford suggests they were influenced by the art critic Louis Edmond Duranty's appeal in his pamphlet "The New Painting" for a revitalization in figure painting: "Let us take leave of the stylized human body, which is treated like a vase. What we need is the characteristic modern person in his clothes, in the midst of his social surroundings, at home or out in the street." 
After Cassatt's parents and sister Lydia joined Cassatt in Paris in 1877, Degas, Cassatt, and Lydia were often to be seen at the Louvre studying artworks together. Degas produced two prints, notable for their technical innovation, depicting Cassatt at the Louvre looking at artworks while Lydia reads a guidebook. These were destined for a prints journal planned by Degas (together with Camille Pissarro and others), which never came to fruition. Cassatt frequently posed for Degas, notably for his millinery series trying on hats.