The Idea Catches On:
Other nations soon began issuing their own stamps. Rowland Hill's adhesive stamps saved money and were easy to use. By 1850 seven countries other than Great Britain were using stamps to signify prepayment of postage. The stamps reproduced here can be viewed in the "Stamps Around the Globe" exhibit.
Most early stamps featured images of famous leaders or numbers representing fees paid. Within the next century, the diversity of topics expanded rapidly.