Robert Indiana kept a series of illustrated journals during the late 1950s and 1960s, in which he discusses the development of his work.
In his journal page for April 29, 1962, Indiana relates that he spent most of the day in, doing things around the loft, and working on his still uncompleted constructions from 1960. The page includes a sketch of Mate, to the left of which Indiana comments that what "[was] probably intended to be Martha [was] dubbed anew today in wh[ite] gesso and reduced [to] include 1962." Also illustrated are a stenciled M and a detail of the work's profile. Below he sketch he records the work's medium (wood, oil, iron and gesso) and its dimensions (40 3/4 x 12 1/2 inches). Added at a later date, to the right of the sketch, is the work's provenance, the Lipmans (who acquired the work in 1962), and the Whitney Museum of American Art (which received the work from the Lipmans in 1966).
Indiana also records that on this day he finished the sculpture Bar.