During the Sengoku, or Warring States, period, Japan was divided into many clans vying for supremacy. Can you name the most powerful clans of this period?
Naming customs in Japan put the family/clan name first, so many famous historical figures from Japan are known by their last, personal name. Thus, personal names are accepted for prominent family heads.
As for the "Middle Ages" thing, I agree that it's a misnomer. Many places, especially in Asia, still advanced a lot during this period, and Japan is no exception. And when Ieyasu (from the Tokugawa clan you saw above) finished uniting Japan in the early 1600s, it led to a long, peaceful era of prosperity for the islands. Pretty cool, huh?