Liberia was the first African country to issue pictorial stamps, many of which were cancelled to order and sold to collectors. Waterlow and Sons, Ltd., London, made a 1-dollar issue available on September 1, 1862. The issue depicted a pygmy hippopotamus. It was printed in sheets of ten (2x5) as part of a set of twelve and then, eventually, seventeen. Because the U.P.U. letter rate from Liberia was only five-cents, it is unlikely that many of these stamps saw postal service. A quantity of these stamps was overprinted in London with ‘Official’ and sent to Monrovia, along with other stamps in the set, for use as government mail (Scott O10). Two years later, postal authorities asked Waterlow and Sons, Ltd., to send another shipment of official stamps, this time overprinted ‘O S’ (Scott O23).