Titles in the United Kingdom

In medieval and early modern Europe, a tenant-in-chief (or vassal-in-chief) was a person who held his lands under various forms of feudal land tenure directly from the lord paramount to whom he did homage, as opposed to holding them from another nobleman or senior member of the clergy. The tenure was one that denoted great honour, but also carried heavy responsibilities. The tenants-in-chief were originally responsible for providing knights and soldiers for the king's feudal army.

title from the feudal system of manorialism

use of courtesy titles in the United Kingdom

1927 law changing the title of British king and parliament