Article: By the end of the 12th century, samurai became almost entirely synonymous with bushi, and the word was closely associated with the middle and upper echelons of the warrior class. The samurai were usually associated with a clan and their lord, were trained as officers in military tactics and grand strategy, and they followed a set of rules that later came to be known as the bushidō. While the samurai numbered less than 10% of then Japan's population, their teachings can still be found today in both everyday life and in modern Japanese martial arts.

Question: What were samurai affiliated with?
a clan