I came across an article in a July 1994 Smithsonian Magazine by author Verlyn Klinkenborg in which he compares these two giants of illustration, in his words: totally American, yet not at all alike.
Like me, Klinkenborg is certainly not an art historian, and, unlike me, a very learned and competent writer who appears to write about all sorts of things for The New York Times and other prestigious journals, certainly The Smithsonian Magazine being one of them.
It's been evident from all the hits and page views this weblog receives, that both Pyle and Rockwell seem to be the most popular worldwide (most of our viewers reside in countries other than the United States.)
Copyright 1959 by the Curtis Publishing Company.
Rockwell's painting, A Family Tree, appeared as the cover of the October 24, 1959 issue of the Saturday Evening Post. As homage to Pyle he says he put the initials H.P. on the treasure chest at the bottom of the painting to acknowledge his copying the galleons from Pyle's earlier work. Click on image to enlarge it.
I believe this is the chest in question, since it has remained throughout time one of the most popular of Howard Pyle's illustrations. You can see much more of his work here, and that of Norman Rockwell here.
Scroll down for each link because this portion will appear at the top.
Title page of the article.
Howard Pyle in his studio, photo courtesy of the Delaware Art Museum.
Norman Rockwell in his studio, courtesy ot the Norman Rockwell Museum, Stockbridge, Massachusetts.