"Sun Horse, Moon Horse" is a colorful and detailed celtic design of two winged horses - one for the Sun, one for the Moon. Knotwork designs surround and include them, with other intricate borders appearing on their bodies.
Above and below are wide borders with a design of interlaced dogs separated by the faces of the Sun (above) and Moon (below). The Moon shows her four phases across the border.
"Sun Horse, Moon Horse" is also the name of a powerful, short book by Rosemary Sutcliff; the book is about the nature of art and the nature of leadership, and the creation of the Great Chalk Horse of Uffington. This painting has no connection with that book other than its title.