The Saracens are an offensive civilization with particularly strong camel and naval units.
Their unique technology grants Camels and Mamelukes extra hitpoints, allowing them to dominate almost any enemy cavalry unit they encounter. Camels normally are unable to stand up to Imperial Age heavy cavalry but this makes up for this, making them more cost effective. This makes them powerful against civilizations that rely heavily on cavalry such as the Huns, Franks and the Mongols which all have cavalry bonuses. The Mameluke is one of the most effective cavalry counters in the game, capable of taking down nearly any cavalry unit and in groups can easily handle War Elephants. However they are a versatile unit and can handle most enemy soldiers.
The Saracens also have a strong navy, with their Galleons having a faster attack than normal and their transport ships have more hitpoints, making it more difficult for opponents to sink a naval invasion. In addition they have twice the carrying capacity so population space is saved when planning a naval invasion.
They have access to all siege weapons except for the Heavy Scorpion giving them strong offensive capabilities. They have full archer technologies and their archers also do bonus damage against buildings. This allows Cavalry Archers to become devastating raiders as this bonus allows them to raze buildings with ease.
Their main weakness is in their heavy cavalry. They cannot upgrade their Knights and are the only Old World civilization to be missing this ability. Fortunately the Mameluke's versatility makes up for this. They also cannot research several economic technologies. Their defense is merely average as powerful Tower upgrades available in the Imperial Age are closed to them. Thus, there's no advantage to help stop a determined attack.