Complex sentence: The Red Army's initial strategic withdrawal relegated the armoured forces to a secondary role, however one important development took place shortly before the war which was to influence Soviet armoured doctrine and tank design for a decade: the creation of the T-34.
Split into simpler sentences: The Red Army's initial strategic withdrawal relegated the armoured forces to a secondary role. However, one important development took place shortly before the war, which influenced Soviet armoured doctrine and tank design for a decade: the creation of the T-34.