Definition of "Nicholas"

Sirrah, if they meet not with Saint Nicholas’ clerks, I'll give thee this neck.

1591 (date written), William Shakespeare, “The First Part of Henry the Sixt”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene i]

I must call you Nick—we always did call you young Nick when we knew you meant to marry the old widow. Some said you had a handsome family likeness to old Nick, but that was your mother's fault, calling you Nicholas. Aren't you glad to see me again?

1871–1872, George Eliot [pseudonym; Mary Ann Evans], chapter LIII, in Middlemarch […], volume III, Edinburgh, London: William Blackwood and Sons, book V, page 182