Ancient Warfare   Hey Dirk You gave a good answer to my question concerning the Roman tactics of bringing provinces into the Empire and I read your similar question and I may have an answer for you There are a couple of major reasons as to twhy Alexander was able to take his army so far in so short a time Alexander had the advantage of inheriting a great army from his father and the Macedonian Empire saturated with I believe silver  Another major factor was the Persians  they had a large army of hundreds of thousands mostly conscripted agaist their will and treated very poorly When Darius was defeated he actually was treated like a liberator and could have easily not only absorbed the remnants of the Persian army but gained more volunteers  Anyway thank you for your response to my question