The Marquess of Salisbury holds the subsidiary titles of Earl of Salisbury (created 1605), Viscount Cranborne (1604), and Baron Cecil of Essendon (1603). The title Viscount Cranborne is the courtesy title of the eldest son and heir of the Marquess.
The title Earl of Salisbury has a complex history. It was first created for Patrick de Salisbury in the middle twelfth century. It was eventually inherited by Alice, wife of Thomas Plantagenet, Earl of Lancaster. When the Earl of Lancaster lost his titles and was executed for treason in 1322, the Countess surrendered all of her titles to the King, and the titles lapsed.
The title was created for a second time in 1301 for William Montacute. It was inherited later by Richard Neville, upon whose death the title went into abeyance because multiple individuals were entitled to inherit it.
Then, in 1472, it was granted to George, Duke of Clarence. When the Duke of Clarence was 1478 for treason (supposedly by being drowned in a vat of Malmsey wine), the title was forfeit. It was then granted to Edward of Middleham, who later became Prince of Wales. Upon Edward's death, the title became extinct.
In 1485, the abeyance of the second Creation was terminated, and the title went to Edward Plantagenet, Richard Neville's grandson. Edward was executed for high treason in 1499; the title was, however, officially forfeit in 1504. Edward's sister, Margaret, regained the title in 1513, but she too forfeit the title in 1539.
The title was given to Robert Cecil, 1st Earl of Salisbury, a close advisor to James I. Cecil was the son of Queen Elizabeth I's chief advisor, William Cecil, Lord Burghley. The present Marquesses still hold the title of the Cecil creation.
Earls of Salisbury, first Creation (c. 1149)
Earls of Salisbury, second Creation (1337)
Earls of Salisbury, third Creation (1472)
Earls of Salisbury, fourth Creation (1478)
Earls of Salisbury, fith Creation (1605)
Marquesses of Salisbury (1789)