Russian sources mention Swedish-Yem co-operation in 1240 at the earliest; it was then that were mentioned as one of the Swedes' allies in the little-documented Battle of the Neva.
Venemaa allikad mainivad rootslaste ja "jeemide" omavahelist koostööd esmalt aastal 1240, mil neid mainiti rootslaste ühe liitlasena halvasti dokumenteeritud Neeva lahingus.