The meaning and origin of the expression: A cat may look at a king

A cat may look at a king

What's the origin of the phrase 'A cat may look at a king'?

The origin of this proverb is unknown. What is known is that it is found first in print in a famous early collection of English proverbs, A Dialogue conteinyng the nomber in effect of all the Prouerbes in the Englishe tongue, 1562:

Some hear and see him whom he heareth nor seeth not
But fields have eyes and woods have ears, ye wot
And also on my maids he is ever tooting.
Can ye judge a man, (quoth I), by his looking?
What, a cat may look on a king, ye know!
My cat's leering look, (quoth she), at first show,
Showeth me that my cat goeth a caterwauling;
And specially by his manner of drawing
To Madge, my fair maid.

In 1713, Oswald Dykes published English proverbs with moral reflexions. This used various well-known proverbs as a starting point for Dykes' to pronounce his political and social values. In this extract it isn't clear which king he was protecting, as Queen Anne was the British monarch at the time:

Tis very true, Kings do not use to call Cats to an Account for their looks, or their undistinguishing Boldness: But there are many Cats of this Kind, which are too much made of, indulg'd, and encourag'd, 'till they fly at last in the Face of sacred Majesty. In this Sense, it is a true-blue Protestant-Proverb. I do not know whether it was calculated for the Rabble or not; to pur and mew like Cats about a Throne, 'till at length they scratch the Hand that strokes them, and mob their Protector. However, there has been ill use made on't; and it has often been extravagantly misapply'd to Outrage and Violence upon a King's Person, as well in Print, as in some Peoples Mouths.

See also: the List of Proverbs.