Marquess of Salisbury is a title in the Peerage of Great Britain. It was created in 1789 for the 7th Earl of Salisbury. Wikipedia
Creation date: 10 August 1789
First holder: James Cecil, 7th Earl of Salisbury
Heir apparent: Edward Gascoyne-Cecil, Viscount Cranborne
Motto: SERO SED SERIO; (Late but seriously)
Peerage: Peerage of Great Britain
Present holder: Robert Gascoyne-Cecil, 7th Marquess