This souvenir sheet honored the Centenary International Philatelic Exhibition (CIPEX), an event held on the 100th anniversary of the first U.S. postage stamp. Design of the sheet includes reproductions of the first U.S. stamps in altered colors. Stamps cut from the sheet are valid for postage, and are sometimes mistaken for the original stamps by persons who have not checked them against those issued in 1847. The marginal inscription reads: "PRINTED BY THE TREASURY DEPARTMENT, BUREAU OF ENGRAVING AND PRINTING--UNDER AUTHORITY OF ROBERT H. HANNEGAN, POSTMASTER GENERAL--IN COMPLIMENT TO THE CENTENARY INTERNATIONAL PHILATELIC EXHIBITION--NEW YORK, N.Y., MAY 17-25, 1947."