The reasons as to why Thucydides thought that writing about The Peloponnesian War was "more worth it" were legit reasons that people to this day believe. There are three reasons as to why Thucydides had claimed this to be true. The first was that the Spartan and the Athenian sides were at their peaks in terms of their power and were very well prepared for war at that point. This point is supported by his exact words "My belief was based on the fact that the two sides were at the very height of their power and preparedness." (History of the Peloponnesian War, pg 35) The second was the fact that this war was Pan-Hellenic, which means it had affected all of Greek and Non-Greek culture, almost the equivalent of a world war for that time. This too is supported by the evidence from Homer since he gave different names to the tribes such as "Danaans", "Argives" and "Achaeans". (History of the Peloponnesian war, pg 37) The last reason is that this war yielded one of the highest body counts as compared to any previous war fought in the Greek world. Both the Trojan and the Persian wars had something wrong with them that didn't make them great. According to Thucydides the Trojan War lacked enough resources to continue on going with the war, while the Persian war ended up being too short. Thucydides believed these reasons to be important because they had the right evidence behind them and are not based on the first story people heard.
The way he went about into achieving his claims was by gathering information which he believed to be right. He believed that people "had no right to judge (different places and things) by their appearances rather than by their actual (influence)." (History of the Peloponnesian war, pg 41) That is why to him it was very important to provide proper evidence so that people know exactly what happens instead of from their own imagination. Thucydides didn't want the readers to think that he was making the events up in order to "exaggerate the importance of their themes, or of the