determiner

a definite article joined 1) with an adjective and possibly a noun of rank to form an honorific attribution, 2) with a noun of number to go into forming a postpositive title phrase, 3) with an occupation name or a descriptive name to form a surname piece, or 4) as part of a nobiliary after the particle and before a toponym or surname to form a surname piece or part of the postpositive title phrase; the d. is introduced in PS-RULES [PS6], [PS9], [PS11] & [PS13]; the d. is definite, the first word in the honorific title phrase: “The Most Honorable David Davis,” and the first word in the postpositive title phrase: “George the second, King of Great Britain,” and also as the first word in the surname piece with a descriptive name: “Pepin the third, the Short.”