Clash in the knights empire

from the old past there was a great kingdom living peacefully this was a really big empire where there were two legends knights spartan and the legend spartacus .
Suddenly sparta and spartacus discover that enemy who are the vikings are going to invade their empire and steal all the gold and kill their people tribes ,clans and towns ,so a big clash is about to happen and our heros should prepare themselves to clash with vikings all clans tribes escape to castle ,the kings prepare the strategy how to defend their border to stop the this clash and save the castle .