I'm not asking about fraud on the historians part but more the biases or lies the origanal writers would put in to make their side look better.
One example I know if is how I grew up being taught Romans fed Christians to the lions. Now it turns out that was probably just the Churatians trying to make the Romans look bad.
Is there anything like peer review or some formal process historians go through when reading a new text?
"history is written by the winners"
In terms that won't run afoul of Rule 1, "Hahahahaha no." If it were 'written by the winners', how is there still Philippine history, when we of the Philippines have pretty much lost most of the wars we've gone through, including our own war of independence (so impolitely interrupted by the US's colonial ambitions)? How is the Lost Cause still a thing? You will observe that English-language scholarship of the Vietnam War is largely written by US writers, who very notably did not win. The Battle of Midway has been itself written by a loser of the battle, Fuchida Mitsuo, and the material required to debunk Fuchida's lies came largely from the Japanese as well. History is written, period, by those who observe it, on winning, losing, and neutral sides. u/Tiako continues this line of thought here.
As for bias? Here's a secret: It's all biased. All of it. But that is not a bad thing. u/mikedash examines the matter of bias here, and u/Georgy_K_Zhukov does the same here.