Toronto. The German optical firm of Ernst Leitz began as a maker of optical objects including microscopes. In the mid 1920s to keep its factory open and staff working, Leitz began the sale and manufacture of the 35mm Leica camera (LEItz CAmera). Over the years, milestone microscope serial numbers were commemorated by awarding the instrument to a prominent individual. Perhaps this also occurred with camera manufacture.
Regardless, the Leica M3, meter, lens, and case were given to Queen Elizabeth II, an ardent family photographer and ardent collector, by the Ernst Leitz company in 1958. This, according to an article by Lucia Davies on the AnOther Magazine website dated May 18, 2012.
A big thanks and tip of the hat to my good friend, professional photographer, and president of the PHSC, Clint Hryhorijiw, for suggesting this item.