Introduced in 1918, the Model 51 was developed from patents and designs from John D. Pederson of Pederson Device and Irwin-Pederson fame as a hesitation-locked blowback semi-automatic pistol with multiple overlapping safety features and good ergonomics. In addition to the two-line address and patent dates, the slide is marked on the left side with "To Admiral Alfred A. Ellison./Compliments Remington Arms Co., Inc". Appointed to the Royal Navy in 1888, Alfred Astley Ellison achieved the rank of Rear Admiral in 1924 and was also made a Companion of the Order of the Bath. During World War I, he was aboard the HMS Halcyon, a torpedo gunboat turned minesweeper, which helped repel the German Imperial Navy raid at Yarmouth and is credited with one submarine kill. The exact relationship between Remington and Ellison is unknown, but gifts from arms companies to potential influencers of military purchasing decisions are commonly seen as a marketing strategy. Fitted with a set of checkered and riveted hard rubber Remington-UMC grips.