At the age of 23, Wain married his sisters' governess, Emily Richardson, who was ten years his senior (which was considered scandalous at the time), and moved with her to Hampstead in north London. Emily soon began to suffer from breast cancer and died three years into their marriage. Prior to Emily's death, Wain discovered the subject that would define his career. During her illness, Emily was comforted by their pet cat Peter, a stray black and white kitten who had been rescued after he was heard meowing in the rain one night. Emily's spirits were lifted by Peter, and Louis began to draw extensive sketches of him, which Emily strongly encouraged him to have published. She died before this happened, but he continued to make cat sketches. Wain later wrote of Peter, "To him, properly, belongs the foundation of my career, the developments of my initial efforts, and the establishing of my work." Peter can be recognized in many of Wain's early published works.