Both Uses of

patron
in
Don Quixote

" Don Quixote laughed, and asked them to take off the next cloth, underneath which was seen the image of the patron saint of the Spains seated on horseback, his sword stained with blood, trampling on Moors and treading heads underfoot; and on seeing it Don Quixote exclaimed, "Ay, this is a knight, and of the squadrons of Christ!†
Chpt 2.57-58 *

patron saint = saint who supports or looks after

"Thou art very simple, Sancho," said Don Quixote; "God, look you, gave that great knight of the Red Cross to Spain as her patron saint and protector, especially in those hard struggles the Spaniards had with the Moors; and therefore they invoke and call upon him as their defender in all their battles; and in these he has been many a time seen beating down, trampling under foot, destroying and slaughtering the Hagarene squadrons in the sight of all; of which fact I could give thee many examples recorded in truthful Spanish histories."†
Chpt 2.57-58

Definitions:

(1) (patron as in: a patron of the arts)
a regular customer; or someone who gives money or support to an organization, cause, or person
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

In ancient Roman history, patron referred to the more powerful person in a complex client-patron relationship. The term is still used in some cultures today to describe a property owner who is in charge of workers.

Also see patron saint.

Much more rarely, a patron is the proprietor of an inn.