To travel from the Eastern Roman Empire to the Persian Empire in which direction
would a merchant have to go?

answer; i believe the answer is (mesopotamia); modern day

yes based on alexanders actions he deserved the title of "the great". his empire covered about 3,000 miles and he was able to establish the empire over a 13 year period of time. he was able to conquer many different places. he also defeated the persians. he conquered egypt and developed a city and named it after himself.