From the manor of Temple, in Wellesborough, Leicestershire, which name was given by the old Earl of Leicester, one of the Knights Templars, who usually gave the name of Temple to their lands.

Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.

TEMPLE. The pveceptorles or priories of the Knights-Templars were often called Temples, as Temple-Bruer, Temple-Newsham, &c., and even manorial residences and estates, belonging to them, obtained the same dignified appellation. The tenant or bailiff of such a property was sometimes kuQwn by the surname At-Temple, or Templeman ; for example at Sompting, co. Sussex, where this order possessed lands, Peter at Temple is named in the Nona Eeturn of loil. In the previous centmy, De Temple, Du Temple, Le Templer, &c., occur in H.R.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.