Why Is Sancho Panza Called Don Quixote

Sancho Panza is an illiterate peasant laborer who agrees to be Don Quixote's squire in hopes of becoming governor of an island as a reward for their adventures. At first, Sancho is a timid character. He is simply there to do as Quixote says, and receive his island. Gradually, however, Sancho becomes more talkative, full of stories, and a believer in Don Quixote's madness.
An island, in many ways, can be a symbol for solitude. As there is water on all sides, it could be interpreted as a somewhat sanctuary for Sancho Panza to govern over. As presented early on in book one, Sancho is quite a selfish man. He leaves his sheep, his wife, and his children for months at a time to accompany Quixote on travels he knows are quite frankly insane. Sancho never lets Quixote forget about his promise of an isle. He, many times, asks if he will get his isle and Quixote assures him every time that he indeed will. As they treck on their journey they meet with a Dutch and Duchess and entertain them so well, Sancho's promise is finally granted. He is presented with his own island.
Before Sancho leaves to govern on his isle, Don Quixote gives him some advice. Don Quixote tells Sancho many things that are needed to be a good leader and it appears that Sancho does a good job of following his advice. Don
But he is also extremely good at making judgments on every day, practical things like money and livestock. He makes a few decisions at which "Everyone was amazed and began to look on their governor as a second Solomon"(Cervantes