Complex sentence: According to that tradition, this ("Prima Maximiana Thebanorum ") was a legion from Thebes that was ordered to move by Maximian, and therefore it is sometimes related to I"Maximiana Thebanorum".
Split into simpler sentences: According to that tradition, this ("Prima Maximiana Thebanorum ") was a legion from Thebes that was ordered to move by Maximian. Thus it is sometimes related to I"Maximiana Thebanorum".