This is the furthest I have ever gotten in Age of Empires II on Hardest difficulty. I finally completed the Horns of Hattin, and was it a struggle, but luckily I did so on the first try.
The key to this stage is to make use of units that don't require any gold. So my army consisted of Pikemen (for cavalry), Light Cavalry (for archers and siege weapons), and Elite Skirmishers (for archers and infantry).
It cost me a lot of units, but after defeating the British (red) I got rid of their Crossbowmen which was a thorn in my side in the beginning of the stage.
The Templars (Yellow) harassed me with their Siege Weapons, mainly catapults. They were no much for my light cavalry, and eventually I broke through and annihilated their production buildings.
It wasn't long after that where I secured victory when I broke through the defences of the Hospitaliërs (orange).
I am making progress, slowly, but surely, and having fun doing so.
Strategy/2D Real-Time Strategy