This section is from the book "The National Capitol. Its Architecture Art And History", by George C. Hazelton, Jr. Also available from Amazon: The National Capitol Its Architecture Art and History.
By a joint resolution of June 23, 1836, a committee was appointed to " contract with one or more competent American artists for the execution of four historical pictures upon subjects serving to illustrate the discovery of America, the settlement of the United States, the history of the Revolution, or the adoption of the Constitution, to be placed in the vacant panels of the rotunda, the selection of the subjects to be left to the choice of the artists under the control of the Committee." It was under this authority that the remaining large panels of the rotunda were filled with pictures. They are, however, purely fanciful, not historical.