One of the surest tests [of a poet’s superiority or inferiority] is the way in which a poet borrows. Immature poets imitate; mature poets steal; bad poets deface what they take, and good poets make it into something better, or at least something different. The good poet welds his theft into a whole of feeling which is unique, utterly different than that from which it is torn; the bad poet throws it into something which has no cohesion. A good poet will usually borrow from authors remote in time, or alien in language, or diverse in interest.
T. S. Eliot, p. 114 in The Sacred Wood: Essays on Poetry and Criticism, 1920
Likewise, a good illustrator welds the theft into a whole of feeling which is unique, utterly different and sometimes even funnier than that from which it is torn.
2018-02-18, update: 2018-12-02
You find many renderings of John Martin‘s The Bard in the Internet. I think that in this comparison the left one is the right one and that the right one is not John Martin’s.
In Henry Holiday’s illustrations to Lewis Carroll’s The Hunting of the Snark there are several references to John Martin’s painting.
2017-09-13, update: 2018-10-11
Bycatch (found in 2013) from my Snark hunt:
initial post: 2017-09-26
[left]: Illustration to Lewis Carroll’s The Hunting of the Snark (1876) by Henry Holiday: The Vanishing (detail from lower left side depicting some weeds which seem to have some fun with each other)
[right]: John Martin: The Bard (ca. 1817, detail from lower left side, retinex filtered and vectorized)
Usually elements borrowed by Henry Holiday from other artists are inconspicuously integrated into Holiday’s illustrations. Here is an exception. The monstrance-shaped tree is just a small element in John Martin’s The Bard. In Holiday’s illustration it is more prominent.