Later years
In 1868, Gilbert wrote The Doctor of Beauweir, an autobiography, told from the point of view of a South Wales medic. King George's Middy (1869), also illustrated by W. S. Gilbert, relates the adventures of a Leicestershire squire's son who becomes a midshipman and is marooned of the coast of Africa. Another 1869 novel was Sir Thomas Branston. Later that year, Gilbert produced his most famous biography, Lucrezia Borgia, Duchess of Ferrara: a biography: Illustrated by rare and unpublished documents. In this work, Gilbert concluded, after extensive research, that there was no evidence of the acts of gross immorality of which Borgia was accused, including murder. This was followed in 1870 by The Inquisitor, or the Struggle in Ferrara, about the life of Renée of France, Duchess of Ferrara, set in 1554.
In 1871, the novel Martha was followed by The Landlord of the "Sun", again describing a descent into degradation, this time involving a villainous seducer, an illegitimate child and drunkenness, and, in 1873, by Clara Levesque. Another theme that was seen in Gilbert's writings was his dislike of established religion and the Roman Catholic Church in particular. Two works on this theme included Facta non-Verba: a comparison between the good works performed by the ladies in Roman Catholic convents in England, and the unfettered efforts of their Protestant sisters (1874) and Disestablishment from a Church point of view (1875).
Gilbert had a mercurial temper and was difficult to live with, imposing arbitrary restrictions on his wife and daughters. After many years of strained relations with his wife, Gilbert left home and separated from her in 1876 after forty years of marriage. He left his wife and daughters substantial incomes and the family home, assuming that he would be able to earn a good living from his writing. However, he soon became seriously ill and appeared to be dying, and his doctors advised him not to write. His wife did not assist in his care and did not, ultimately, allow him to return home. Her son appealed to her on his father's behalf, but she would not change her mind. W. S. Gilbert apparently never contacted his mother again. Instead, Gilbert went to live with Jane, his only married daughter, and her husband in The Close at Salisbury Cathedral, where he resided for the rest of his life.
In 1877, Gilbert published Them Boots, another description of characters from the lowest class of society, as well as The City. Pursuing another favourite theme, the dangers of drink, Gilbert also published in 1877 Nothing but the Truth, an unvarnished picture of the effects of intemperance, and example of his many writings about the dangers of alcohol. 1879 saw the publication of Mrs. Dubosq's Bible, about a French Huguenot group in Spitalfields in the 18th century, and the possession of a 1650 Geneva Bible by a poor person. In 1880, Memoirs of a Cynic was a protest against cruelty and hypocrisy. This was followed in 1881 by Modern Wonders of the World, or the new Sinbad, a series of 10 stories told to London children by Hassan, the son of an Egyptian slave dealer. His last book, published in 1882, Legion, or the modern demoniac, returns to Gilbert's campaign against drink, which, he illustrated, leads to "crime, profligacy, suicide, homicide, brutality, cruelty, pauperism, idiocy and insanity."
Gilbert died at the age of 86 and was buried in The Close at Salisbury.