hi candice,

the little castle symbols are signs for castles, important manned towers and fortifications. The little flags are signs for ruins and lost or legendary places and towns/cities. The X icons are crossed swords and in fact, they are marking battlegrounds from the past.

In the north we have the old battlefields of the fight against the dark hordes (about 1000 years before), in the center left we have the battlegrounds of the ages, where humans fought against elves (about 600 years before) and in eastern Aegeria we have the places, where Aegerian fought against the expanding Danskar Northmen. (starting about some 30 years before but ongoing till Aegeria was captured by the Wallungians)