The terms poruka (suretyship or collective responsibility) and poruchnik (surety, guarantor) rarely appear in pre-Mongol Russian texts. Formal poruka seems to have expanded enormously only after the Mongol invasion. The institution clearly flourished in Muscovite Russia, where q“surety bonds” (poruchnye zapisi) were drawn up to cover debts and contractual obligations, military and administrative service, payment of fiscal levies, obligatory labor, trial procedure, personal conduct, public safety, political allegiance—and even matters of conscience and orthodoxy (“spiritual suretyship”). In all those areas, individuals or groups of people could, as “sureties,” be held responsible for the conduct of others, the “principals.” Sureties faced harsh penalties—fines, forced labor, corporal punishment, and worse—for their principals' misconduct or failure to fulfill certain obligations.