The original. The one with Altair as the protagonist.

Yeah it wasn't that good but at least it set the standards of the series! The game also had Damascus and a third city that I can't remember.

The story was fine in my opinion, it was actually quite different to other games at the time... the thing that most people, myself included, didn't like, was that it was extremely limited in the gameplay department, as in there wasn't enough variety of missions and it was EXTREMELY repetitive, moreso than any other game in the series, not to mention there were sections in the game that seemed incredibly unnecessary too... but yeah I'd definitely say it's worth playing anyway, it's a cheap enough pick up these days, and if you want to see Jerusalem or Damascus, this is your best chance, lol... although it probably won't wow you like it did with the rest of us that played it back in 2007, since the graphics now will be substandard to what you're used to.

It was alright as far as I remember. Nothing super special but a bit mysterious at times. The cities looked kinda nice but it's an early game in its generation so I'm not sure if it aged that well. If you're a fan of the series then you should definitely pick it up! I didn't play the whole game myself, instead I watched a friend of mine playing through it.

It is also by far the closest Assassin's Creed game to real life history's "Assassins" (In arabic, Hashasheen) a mysterious independent group of anti-crusader and anti-government (Seljuk Dynasty) rebels. It takes place around the time of Saladin and The Fatimid Caliphate.