The Icelandic horse is a small breed of horse

The Icelandic horse is a small breed of horse that has evolved in isolation in Iceland as said here. Archeological finds in Norway, where the Icelandic horse is descended from the vikings, have revealed that the Icelandic horse belongs to an ancient race that died out in other parts in Europe but survived in Iceland for 1100 years without crossbreeding. 

The Icelandic horse is small, weighing between 330 and 380 kilograms (730 and 840 lb) and standing an average of 132 to 142 cm (52 to 56 inches) high. It has a spirited temperament and a large personality. It comes in a wide variety of colors,  and the Icelandic language includes more than 100 names for various colors and color patterns of the Icelandic horse. 

The Icelandic horse is known for its sure-footedness and ability to cross rough terrain. It displays two gaits in addition to the typical walk, trot, and canter/gallop commonly displayed by other breeds. The first additional gait is a four-beat lateral ambling gait known as the tölt. This is known for its explosive acceleration and speed; it is also comfortable and ground-covering. The breed also performs a pace called a skeið, "flying pace". It is used in pacing races, and is fast and smooth, with some horses able to reach up to 50 km/h (30 mph). It is not a gait for long-distance travel. More about the icelandic horses gait here