What are the 4 original breeds of horse that all other derived from?

The four original horse breeds that all others are derived from are the Arabian, Barb, Thoroughbred, and Quarter Horse. The Arabian is known for its speed and endurance, while the Barb is known for its agility and strength. The Thoroughbred is a cross between the Arabian and Barb, and is known for its speed and stamina. The Quarter Horse is a cross between the Thoroughbred and the Barb, and is known for its speed and agility.