Uh....don't hate me for this, but things didn't exactly go very well. Things started out okay, but kinda went downhill towards the end.
Pre-turn: I change our attack plans a bit. Attacking Aydin would only delay our troops from reaching the real Ottoman lands. I move our units south towards Iznik.
510 BC: Mecca Settler -> Spear
Baghdad Sword -> Worker
Mecca's spear goes with Settler as an escort, they will be sent to Greek Island.
Some barb hunting.
490 BC: Kufah Sword -> Temple
Basra Temple -> Spear
Khurasan Spear -> Temple
Mansura Worker -> Spear
Barb camp dispersed.
Dark green border spotted!
470 BC: Mecca Spear -> Horse
Medina Barracks -> Palace(prebuild)
Baghdad Worker -> Horse
Najran Galley -> Temple
Aden Temple -> Spear
Okay, our mighty Horsemen are ready for glorious battle! War is honorably declared against the Ottomans.
A wandering Otto warrior is killed.
Two Horsemen manage to capture Iznik with practically no opposition!
450 BC: Damascus Sword -> Temple
Fustat Horse -> Galley
Muscat Spear -> Temple
Gems are connected!
Lots of barb hunting in the northern tundra.
430 BC: The green border turns out to be the Aztecs. We make contact.
We trade all of our contacts (Ottos, Indians, Greeks, Babs), for Mathematics, Contact with Egypt, and their WM.
Egypt contacted. We trade just our WM to them for their WM and all of their 203 gold.
A teal border is visible across the water from Egypt, but no contact is possible yet.
410 BC: Mecca Horse -> Harbor
Basra Spear -> Galley
Resistance in Iznik ends.
Barb camp dispersed.
390 BC: Damascus Temple -> Worker
The city of Merw is founded on the Greek Island with Wheat and Cattle in range.
Our Horses are now in position to attack Istanbul. However, I hold off for a few turns to await the arrival of some swords.
370 BC: Cleo whines about our galley in her territory...
An Ottoman Archer attacks a Horse and retreats it.
Damascus Worker -> Horse
Baghdad Horse -> Worker
Fustat Galley -> Worker
Indians start Lighthouse.
Philosophy sold to Aztecs for 64 gold. Just trying to keep the tech pace moving.
350 BC: Osman comes begging for peace. I laugh in his face.
He responds by attacking one of our Swords with an Archer. We redline, but win.
Oh, I see a foreign border across the water to the SW of Greece.
Okay, now is the battle for Istanbul! First, I attack a Settler/Spear pair. Two new slaves for us

Now for the attack on the city itself.
A Reg Sword dies. Another Reg Sword dies.
A Vet Sword dies. A Vet Horse dies.
A Vet Horse wins (yay). Another Vet Horse wins.
A Vet Horse dies. Another Vet Horse wins.
....Ack!! There is only a redlined Spear now defending Istanbul, but I have no attackers left to kill it!!
Maybe next turn.
330 BC: Alexander whines about our galley in his territory.
Baghdad Worker -> Sword
Aden Spear -> Harbor
Kufah Temple -> Worker
Okay, let's try this attack again.
Reg Sword attacks Istanbul, and dies.
Vet Horse attacks and DIES!!
That's it, I can't attack Istanbul anymore. Our offensive has failed. Only a few injured units remain just outside of Istanbul's radius. Our army is now in shambles....
I could certainly blame the RNG for my failure. But, I can only blame myself for bad strategy. I probably could have won if I hadn't retreated nearly all the injured units. I should have kept them there to attack the next turn.
It's not hopeless, though. Once those injured units heal up, they still might be able to take the city. Istanbul now has two Spears, but any more reinforcements are unlikely within the next few turns.
In other news, there's a Galley to the Southwest of Greece. It can be sent directly West to gain contact with that yellowish border.
Here's how the world looks now:
And here's the save:
The Save