One of Polybius's great contributions to historical theory is his emphasis on the interrelationship between historical phenomena. He has a broad vision, and the history of Mediterranean countries and nations occupies a certain proportion in his book. He claimed that the history he described began in 2 18 BC, because from then on, the history of all countries began to become a related whole, and the historical facts that happened in Italy, Libya, Greece and various parts of Asia all influenced each other, and the development trend of all these historical facts was finally unified. In this way, it is meaningless to write about individual events. Only by putting events in the background of the world can we fully understand their significance.

It is certainly not easy to do this. Polybius believes that historians must have a meticulous spirit of seeking truth, insist on independent thinking and never follow the trend. His own general history embodies this spirit. He personally visited many ancient battlefields, carefully collected information and selected the achievements of predecessors. In this respect, he is Thucydides' most faithful successor.