The discussion of the Narragansett and its cousin, the Canadian, Pacer is pretty well known. There’s no reason to repeat it here.
The Iberian connection deserves some comment. The Spanish colonies of the New World predate the Northern European colonies by at least a couple of centuries. During that time Spanish explorers roamed by sea as far north as the Canadian Maritime provinces. Land expeditions reached the headwaters of the Tennessee River. Spanish missionaries reached as far north as present day St. Louis. While much of this exploration was by boat, there was a lot of land travel, also. Horses and mules (and oxen) were part of the “train” of these explorations. While the working horse in the Iberian culture is the stallion (who is almost never gelded) mares and jennies would have been used from time to time.
During the period from the early exploration to the rise of the U.S. And the Louisiana Purchase there was a brisk, if illegal, trade in horses, tobacco, and other goods between the lands west of the Appalachians and the Spanish settlements further west. For a time even New Orleans was under the rule of the Spanish Crown. This means that the horses in use would likely have been Iberian as they were available in numbers and would have been relatively inexpensive.
As noted, gait can occur in any trotting breed from time to time. Today it is pretty much ruthlessly suppressed. In the Age of Horsepower it would have just sold off to somebody who needed a gaited horse for longer distance travel astride. Anything else would have been “wastage.” Such generally did not occur in a frontier society.
Significant numbers of “American” horses (of Northern European origin) did cross the Appalachians, particularly after the Louisiana Purchase. Lewis and Clark noted the types of horses in the log of their journey west. They found no trouble getting horses when they had to abandon river travel.
The “gaited” horse in North America today is really a horse that developed in the Appalachians in the early to mid-19th Century. Roads in this area were poor and travel conditions could be difficult over a large part of the year. A good “road horse” (comfortable, reliable, versatile) was a necessity.
Communities were also rather isolated. In a time when travel was difficult many people never left the valley they were born in. Their world was defined by ridgelines and bottom land. So the base stock available to them would have been a mix of American and Iberian horses. This also meant that the breeding practices of the day would be crucial in establishing regional types.
During this period a stallion owner would “campaign” his stud horse in his valley to build a name for himself and the horse. Races, demonstrations, and the “Saturday Night Horse Show” were primary venues. He would then offer the stallion for breeding. His method was to travel around his valley (and maybe some adjoining valleys if the horse was good enough) and stand it to local mares. Dominant stallions very quickly put their mark on local equine populations. Pedigree was less important than breeding performance and the quality of the get. In time a system of “papers” would arise, but it was very informal and, probably, somewhat inaccurate. We have DNA testing today because of the shenanigans of horse breeders. I doubt the horse breeders of the 19th Century were any more ethical!
The Civil War meant that huge numbers of these locally bred animals would be pressed into military service and would leave their isolated valleys for the larger world. The Union Army did not use gaited horses. The Confederate Army didn’t want to, but had no choice. The Union Army issued the trooper a horse. In the Confederate Army a trooper provided his own horse. If it were lost in the line of duty he would either be issued a new one or paid the value of the lost horse. Many Union officers learned the benefits of a smooth horse and would seek them after the War, spreading them a bit further out. There was always a prejudice against the gaited horse by some “professionals.” This shows up from time to time in the equine literature of the day.
After the War the Appalachians settled back into the pattern that had persisted before. It would not be until after WWI that more modern development would come to Appalachia. This would also be the era of the rise of the various breed associations. By the 1930s the horse was losing its job to the auto in massive numbers. No longer a necessity, the breeders sought to make it a luxury good. In doing this they needed to create a market and one way to create that market was to make their particular horse a “pedigreed horse” with a bloodline capable of producing “bragging rights.” The first to successfully do this were the TN Walker breeders. Others would soon follow.
After WWII the isolation of the rural South was pretty well erased. The War had given the horse a short period of gainful employment (due to gasoline rationing and the difficulty in maintaining automobiles) but by the late ‘40s the Age of Horsepower was over. From then on horses would be a pastime, not a necessity.
Whenever you read about the history of a gaited breed keep in mind that this is the historical context in which that breed developed. Practically speaking, this means that much of the “history” that is claimed will be myth and legend writ down. That does not mean everything is false, only that it’s been “spun” to appeal to the ego of a potential buyer.
If you have any further interest in the equine history of North America I commend to you three works:
Conquerors: The Roots of New World Horsmanship by Dr. Deb Bennet.
The Spanish Frontier in North America by David J. Weber
Los Mesteños: Spanish Ranching in Texas, 1721-1821 by Jack Jackson.