1913 Great Britain, "Brittania Rule the Waves"

When sculptor Bertram Mackennal first submitted his designs for King George V's low value definitives, he proposed a larger stamp format for the high value denominations, offering more room to work with. He created an image of Britannia driving a chariot through rough seas, drawing on classical sources for inspiration. The King, himself a devoted stamp collector, took a personal interest in the project and suggested several changes, including replacing the denomination shown on Britannia's shield with the Union Flag and adding harness to the horses pulling her chariot.

Mackennal's revised artwork was completed by March 1911, and the King further recommended that the stamps be printed using the recess, or intaglio, method, in which paper is pressed into the engraved recesses of a printing plate, producing a richer appearance than the letterpress process used for lower value stamps of the era. Engraver J.A.C. Harrison cut the dies from Mackennal's design, and the finished stamps, printed by Waterlow Brothers and Layton, finally appeared between June and August 1913 in four denominations and colors, the half crown in brown, five shillings in red, ten shillings in blue, and a pound value in green.

Collectors quickly nicknamed the set the Seahorses, and the design remained in production for over two decades, passing through several different printers over the years while retaining its dramatic imagery of Britannia commanding the sea. Issued on the eve of the First World War, the stamps carried an unmistakable message of naval strength and imperial confidence at a moment when major world powers were competing for position on the world stage. More than a century later, the Seahorses remain among the most celebrated and widely collected classic stamps of Great Britain, prized both for the artistry of Mackennal's design and for the turbulent era in which they first appeared.