A reenactment of an onslaught of Kievan Russian warriors (9th-11th centuries). Reenactors and creators of the weapons, shields, helmets etc, are unknown: kudos to them for their fine work.
The warriors wear a variety of spangenhelms (Continental and Scandinavian types) or solid Norse helmets, and are armed with axes and swords. At least two warriors wear mail armour, and many helmets bear mail neck-protectors.
This is a map of the Kievan Rus state in 1054, at its greater extent, just before the death of Yaroslav I (credit: Wikimedia commons). In 1054 the state was divided in a number of independent principalities, a process that had already started before that year.