During design and construction the Building Committee of the American Congregational Association agreed on a series of four bas-reliefs should be included in the second story facade of the Congregational house, with each relief depicting a fundamental principle of Congregationalism. The tablets are carved from Knoxville marble and bear no inscription as it was assumed the subject of each panel would be known on sight to the average citizen. The reliefs were carved by Domingo Mora, a Spanish sculptor who, catalyzed by the Spanish–American War, left the country and reliefs unfinished, citing his inability to stay and work in a country hostile to his own. The reliefs were carefully completed according to Mora's design by a Swiss modeler known only as Mr. Stadler.