Hello Dale,
Thank you immensely for this mod. I am very happy that something like this exists, because I really enjoy playing on Earth Maps with realistic start locations, especially when just starting to play a new Civ game.
I wanted to comment on the placement choice of two capitals.
If you read Harun's pedia entry, and look him up on the net, you'll find his capital city was Baghdad.
Capital Placement for the Arabs: Arguments in favour of Mecca
I understand why from the quote above you chose Baghdad and this was initially what I figured your rationale might be. While what you're saying is accurate, it is important to know that for a variety of religious, historical and game-related reasons, the present day location of Mecca seems to be a stronger choice for the location of the capital. Here are the arguments I can think of:
1) The modern day Arab language and culture derives from Mecca and the surrounding region (particularly the Quraysh tribe, which dominated the city). This makes it a very logical starting point for the Arabs, especially in the ancient, classical and medieval eras.
2) Mecca is considered the religious heart and holiest city for Muslims, which of course were synonymous with the first Arabs as we know them today.
3) That region, Hedjaz (specifically the nearby city of Medina but also Mecca), became the political centre of the early Muslim community and remained the capital of the growing Islamic empire during the period of the first four ("rightly guided") caliphs.
4) Although the leader of Arabia in this game is Harun Al-Rashid, and the capital during his time was Baghdad, the capital of the Caliphate has changed repeatedly over its history. In fact, a tradition eventually developed in which each new Muslim/Arab dynasty established a new capital as a symbol of "renewal" and a break with the past.
Consider for example Civ 4. The leader of the Arabs in that game was Saladin and under his rule, the capital of the Caliphate was established in Cairo (Egypt) and later Damascus (Syria). However, despite this, the capital for the Arabian empire was chosen to be Mecca in Civ 4 (probably for some of the reasons I mentioned above). In fact, when the Ottomans were in their ascendancy, the Caliphate was reestablished in Istanbul, where it remained until it was abolished in the early 20th Century.
Therefore, Mecca represents a more "timeless" choice that strongly applies regardless of the epoch.
5) The first city (and therefore capital) founded by Arabs in the game is Mecca. This means a computer player, or player that does not rename the city, will found "Mecca" where Baghdad is supposed to be, if that location is kept. The other capital cities however, are named and placed correctly and it looks out of place to see Mecca in modern day Iraq.
6) Moving the location to modern day Mecca would also space out the nearby civilizations and leave Mesopotamia available for settlement by these powers. This area has historically been ruled by the Babylonians, Persians, Romans, Arabs and Ottomans, so it would make for an interesting "prize" for any of these nations based on its very fertile land.
Capital Placement for the Persians: The Location of Persepolis
I also wanted to note that the current location for Persepolis is a bit off. Currently it is not far from Kuwait in Southeastern Iraq. However, it could be moved further eastward in the Iranian plateau to improve realism. (This applies to the Huge map, I don't know about the others).
All of this feedback is only meant to further improve what is a fantastic mod and to offer my own (very minor) contribution. If you would like to discuss further, I would be happy to.
I'm also eager to hear what others think and if they agree with me regarding the placement/choice of Mecca.