We have an FN 1900 to look at today that was purchased by the Russian Imperial Army’s primary Gymnastics and Fencing School (Главная гимнастическо-фехтовальная школа). That was an institution established in 1909 to train officers who would become fencing and gymnastics instructors for the Army at large.
Russian officers could carry private-purchase handguns from a list of approved designs, which included the FN 1900, 1903, and 1905. A bunch of Army schools and institutions bought batches of FN pistols between 1907 and 1914 for resale to officers. These will often, but not always, be marked with a crossed pair of Mosin Nagant rifles.
There was no formal adoption of the FN 1900 by Russia, and so there was no large Army order specifying that crossed-rifle marking. Instead, small contracts were made by institutions, who could make their own choices about how the guns would be marked.
One of the interesting and distinctive elements about these Russian purchases is that while some of their guns were blued, a significant number were ordered with a factory nickel-plated finish, which is rare on FN pistols. This example shows very nicely how FN left a few small parts (magazine release, trigger, safety) in a black primed state instead of plating them. It had been found that when those parts were plated, the change in surface thickness could cause fitting problems.
Thanks to Max Popenker for the marking assistance, and to Legacy Collectibles for the loan of the pistol!