We describe the features of the reserve replenishment formation of the Russian army at the expense of soldiers’ children in the 19th century. We reveal the historical and legal aspects of the social and class status of the “military class” representatives descendants: soldiers’ children, recruits of soldiers’ children. Born in the recruits families and lower ranks during the service period in the Russian army, either retired, soldiers on indefinite leave and disabled veterans, the soldiers’ children had a special social and legal position in the class structure of Russian society, which are specifically regulated, as the legislative and enforcement practices in the capitals and provinces in the Russian Empire in the 19th century. The involvement of a fairly wide range of archival sources and published materials allowed to conduct the reconstruction of both the existing legal regulation and the actual social parameters of the “military offspring” in the armed forces. We also reveal the aspects of education of military cantonists in special military educational insti-tutions and similar military units (military orphan units, training battalions and companies, carabinieri regiments) reflected in the primary archival documents and legislative acts, social and legal, class and everyday conflicts and trends that determined the life and fate of “military chil-dren”. We clarify statistical errors in the calculation of the military class representatives – soldiers’ children – in the Russian province. We give a detailed historiographical study assessment of the legal status of cantonists and recruits of soldiers’ children, as well as identifying research gaps in the works of domestic and foreign historians. We made conclusions about the prospects of the sci-entific problems study by domestic historians, as well as the presence of primary archival docu-ments that need to be introduced into scientific circulation. It is proved that the category of “sol-diers’ children” was the most important component of the Russian armed forces combat capability formation, allowing to prepare a significant reserve. We also show the prospects of the cantonists transformation into professional soldiers, as well as their role in the military history of the Russian Empire in the considered chronological period.