It just bugs me that I can't find why purple was a notable color for the Romans. 
I'm aware purple was very hard to find in their day and that only the richest of the rich could afford to dye their clothes purple, but that wasn't solely a Roman thing...
The other color schemes (for the most part) make sense and are historical. So why is Rome purple? Shouldn't that be the Iroquois (purple and white)? WHAT AM I MISSING HERE?!

I'm aware purple was very hard to find in their day and that only the richest of the rich could afford to dye their clothes purple, but that wasn't solely a Roman thing...
The other color schemes (for the most part) make sense and are historical. So why is Rome purple? Shouldn't that be the Iroquois (purple and white)? WHAT AM I MISSING HERE?!