A Rav told me that when it comes to science and nature, the Talmud can say incorrect things (i.e. about animals, cosmology) because they were going by the Greeks and Romans. (Where he gets permission to say what details in the Talmud we can reject and what we must believe, I do not know.) But he said that the Talmud is considered to be the true and reliable Oral Law when it comes to Halacha and history. So my question is, is the Rav right, and how should we take statements in the Talmud that appear to make incorrect statements about history?
Now, I know for some things, you can argue about what they say. For example, although historians and archeologists dispute a lot of stories the Talmud has on the Churban and actions of Roman Emperors, you can say perhaps the historians made mistakes. And where it discusses Adam and Noah and things like that, you can say they are speaking in terms of whatever allegory it is that Genesis means in the level of Sod.
But there are still things that just cannot be explained away. For example, history of the Persian Period discussed in the Talmud is so different from indisputable evidence that there were more kings of Persia, that the period lasted over 100 years longer than the Talmud and Seder Olam Rabba says (even resulting in our 5776 calendar of being about 165 years too short), that there is no way to say that Achashveirosh was the father of Darius, etc. I also know that not all Rishonim are as faithful to Seder Olam Rabba and what the Talmud says about historical events, so this is nothing new.
But in light of what I was told, how do I answer this question? Must we, can we, further shrink the range of topics in which we can and should trust our Chachamim?