As part of a larger technical study of the sculpture of Henri Matisse, in preparation for the exhibition Matisse Painter as Sculptor (jointly organized by the Dallas Museum of Art, The Nasher Sculpture Center and The Baltimore Museum of Art), six versions of the Reclining Nude I (Aurora) were examined. Comparisons were made through measurements, base tracing, photographs and 3-D computer models from laser scans of all six casts. This paper will discuss variations amongst different casting techniques, different media and between early and late casts. Two bronzes deemed unauthorized casts by the authors of the catalog raisonné will be included in the discussion. Matisse’s overall bronze production in France in the years 1906-1954 will be considered as background information.