First Day Cover: Inauguration of the Isle of Man Post Office, 5 July 1973.
A first day cover (FDC) is a postage stamp on a cover, postal card or stamped envelope franked on the first day of issue.
This envelope is franked with an image showing a Viking ship racing through the waters. Affixed is a 15p stamp showing a Viking warrior, celebrating the Viking landing on the Isle of Man in 938 A.D. The Manx people are proud of their connections to Viking culture, so it is perhaps not surprising that Viking imagery was chosen to celebrate the inauguration of an independent Manx Post Office. From this point in time, only Manx-issued stamps are valid on the island, and similarly, Manx-issued stamps are not valid in the UK or elsewhere.