The Arab is a small light horse with a high head and high croup. Many Arab Horses have 5 lumbar vertebra and 17 sets of ribs, one less than horses of other breeds.
As a war horse the mares were ridden into battle because of their courage and mental strength. Personally, I always thought that would lead to many interesting battles during the crusades since Western European knights rode stallions.
The Arab started coming to Western Europe during the Crusades, when crusaders came home bringing this ‘new’ horse with them. That was around 1095. After that when the Ottoman Turks pushed into Hungary in 1529 they brought Arabians with them.
From there it went on to influence just about every breed in Europe with the possible exception of the Icelandic, since the stud book there was closed around the year 1000.