Concerning its origins, a theory has been advanced by some authors that the Sorraia is a descendant of primitive horses belonging to the naturally occurring wild fauna of Southern Iberia.

Today, the Sorraia has become the focus of preservation efforts, with European scientists leading the way and enthusiasts from several countries forming projects and establishing herds to assist in the re-establishment of this breed from its current endangered status.

[15] Genetic evidence[11] has not supported a hypothesis that the Sorraia is related to the Barb horse, an African breed introduced to Iberia by the Moors.

[16] Multiple authors have suggested that the Sorraia might be a descendant of the Tarpan based on shared morphological features, principally the typical color of its coat.

Paleolithic parietal art images in the region depict equines with a distinct likeness to the Sorraia, with similar zebra-like markings.

[16] Spanish conquistadors took Iberian horses, some of whom closely resembled the modern-day Sorraia, to the Americas in their conquests,[16] probably as pack animals.

[2] Similarities between the Sorraia and several North and South American breeds are shown in the dun and grullo coloring and various physical characteristics.

This evidence suggests that the Sorraia, their ancestors, or other horses with similar features, may have had a long history in the Iberian region and a role in the creation of American breeds.

This remnant herd of primitive horses had continued to live a wild existence in these lowlands, which were rather inaccessible and had been used as a hunting preserve by Portuguese royalty until the early 1900s.

For centuries, peasant farmers of the area would occasionally capture the horses and use them for agricultural work, including threshing grain and herding bulls.

All Sorraias currently in captivity descend from these original horses obtained by d'Andrade, and it is believed that the remnant wild herds of the breed died out soon after.

The refuge created for them is in the Vale de Zebro region of south western Portugal, one of places so named because this is where the Sorraia's predecessors dwelt.

[2] While not bred for a specific use, the Sorraia horses are versatile and have been used in herding bulls, dressage riding and light harness.

Today, the name Marismeño refers to a population of semiferal horses living in Doñana Natural Park in Spain.