I realized I had made a mistake after I declared war on the Norse. They were massing troops at the border. I had a forward city on a large island next to their homeland, and the sea was rife with their soldiers. So I built up a small navy and declared a pre-emptive war. All hell broke loose for year after year, decade upon decade, century to century. I had tons of cannon fodder for land based battles because I had the foresight to choose the Aztecs prior to the war's start. I raised a huge army of peasants. I figured if they invaded I could swarm their superior troops with my willing, barely trained folk army. Other than the fight over one city away from the main war those troops never saw combat. The real action was at sea where the blasted Norse unleashed their naval horde. We both had Quadriremes, but theirs outclassed mine significantly. I kept pumping out more and more ships into each battle, surviving by the skin of my teeth. It wasn't until I got cogs and then entered the Industrial era with German manufacturing superiority that I was finally able to force their surrender. By then they had become the Poles and I'm glad I never had to face those Winged Hussars.

Oh, and I almost forgot. For all that centuries long death and destruction I gained a total of two undeveloped territories and one lackluster city.