It was age of empires 2. The graphics were incredible for its time. Seeing crossbowmen, blunderbusses, castles, siege weapons, ships, villagers all at the same time, great unit detail, the historical characters, the actual strategies, how the battle changes by virtue of the location of the units.

Pd: it all made sense. Except that if you attacked a building with a sword it would catch fire... at my young age that was the first thing I asked my cousin when I saw it.