What makes the Reginald M. Phillips Collection important in the history of the Penny Black?

The Reginald M. Phillips Collection is significant to the history of philately and the Penny Black because it contains the world’s earliest known first day cover (FDC) of the stamp.12

Issued in 1840, the Penny Black holds the distinction of being the world's first adhesive postage stamp. The FDC in the Phillips Collection is particularly valuable to historians and collectors because it features the stamp alongside a postmark from its official first day of issue, providing a rare and definitive record of the stamp's debut.12

Donated by the entrepreneur and philatelist Reginald M. Phillips, this collection also includes other important 19th-century British postal items, such as design essays, die proofs, and the Mulready stationery—the first postage envelopes and letter sheets designed by William Mulready. These materials, once held by the National Postal Museum, are now under the stewardship of The Postal Museum in London.2