by cognomen, designation, pseudonym or sobriquet
And now, O Muse, with song so big,
Turn round to Gainsborough’s Girl and Pig,
Or Pig and Girl, I rather should have said;
The pig in white, I must allow,
Is really a well painted sow,
I wish to say the same thing of the maid.
— John Wolcot (1738-1819), better known as “Peter Pindar,” in his first ‘Ode to the Royal Academicians.’ He refers to Gainsborough’s Girl with Pigs.