Luxembourg 1921 Caritas Souvenir Sheet

Luxembourg · 1921 · 10c, 15c, 20c, 25c, 30c

This is the world's first souvenir sheet, issued by Luxembourg for charitable purposes. It contains five stamps from the 1921 Caritas series, featuring portraits of Grand Duchess Charlotte, Prince Jean, and other members of the royal family as children. The sheet is notable for its ornate border and inscription dedicating the surtax to charity.

Issued in the post-World War I era, this sheet established the concept of the souvenir sheet in philately, combining multiple stamps into a single collectible format often sold at a premium for a cause.