The Shimon Family have been around just as long as the Vongola Family. In fact, Giotto and Cozart, the first two bosses of their respective families, were close friends. But when one day, the Vongola used the Shimon as bait, the Shimon had lost all of their dignity. The Vongola never came to rescue them, and the Vongola also accused them of the incident, causing shame to the Shimon. However all of this turned out to be a plot by Daemon Spade to create the ultimate ideal Vongola. After the crisis was resolved, the Shimon family has then since become an ally of the Vongola again.