And reached for a pen if only to show
We did not just laze in an armchair turning pages;
We pressed a thought into the wayside,
Planted an impression along the verge.
Even Irish monks in their cold scriptoria
Jotted along the borders of the Gospels
Brief asides about the pains of copying,
A bird singing near their window,
Or the sunlight that illuminated their page-
Anonymous men catching a ride into the future
On a vessel more lasting than themselves.
And you have not read Joshua Reynolds,
They say, until you have read him
Enwreathed with Blake's furious scribbling.
Yet the one I think of most often,
The one that dangles from me like a locket,
Was written in the copy of Catcher in the Rye
William Blake had beef with Reynolds, taking particular offense at the latter’s  Discourses on Art . The two had radically different views on the role of art, Blake believing that men were born with artistic knowledge while Reynolds arguing that such knowledge was only gained from experience. Blake also disagreed with Reynold’s emphasis on portraiture. 
 
 Collins alludes to Blake’s famously harsh annotations of Reynolds (see  this article  from the Andrew Graham-Dixon archive for more). On the title page of Discourses on Art, Blake wrote, “This Man was Hired to Depress Art.” Later he went further: 
 Having spent the vigour my Youth & Genius under the Oppression of Sr Joshua & his Gang of Cunning Hired Knaves Without Employment & as much as could possibly be Without Bread, The Reader must Expect to Read in all my Remarks on these Books Nothing but Indignation & Resentment. While Sr Joshua was rolling in Riches, Barry was Poor & Unemploy’d except by his own Energy; Mortimer was call’d a Madman, & only Portrait Painting applauded by the Rich & Great … Fuseli, Indignant, almost hid himself. I am hid.
Marginalia