European king circa 700 AD: You live a glorified log cabin. You poop in a bucket. You wipe with your hand. Your food is mostly burnt slop. You will never eat chocolate, guacamole, pizza, or any style of cuisine that isn't native to your country. Almost all of your time is spent fighting wars on horseback. You sole entertainment is practicing for war. When you go to war, it almost always ends in a bloody, pointless stalemate. Enemies, friends and family are all scheming to kill you in horrific ways. Maybe you have a couple of homely concubines, but better not let any one in the Church find out.
Poverty absolutely is relative. In terms of quality of life, the American working class is far richer than any European king in 700AD