Antonio Corento Espina, 50, is a cattle breeder who has been attending The Saca de la Yeguas for seven years. He swats harmlessly at the mares with a long stick to divide them into different groups according to their owners. (David Rengel)

During La Saca de la Yeguas festival on June 26, horses are led from Doñana to Almonte, and into Rocio, a world-famous center of pilgrimage. Here a breeder leads mares through the streets of the village of El Rocío. (David Rengel)

The population of feral horses, or mustangs, greatly decreased in the United States during the 20th century. The modernization of the countryside, extreme weather conditions, indiscriminate hunting and human pressure have all led to the slow demise of wild horses. But in an area of southern Spain, the heritage and lines of the mustangs live on.

From 1493 to 1512 an estimated 500 horses traveled on ships to the Americas. This importation of livestock along with their breeders from the marshland of the Guadalquivir River on Spain’s southern Atlantic coast had a clear impact in the New World. In 1971, Congress recognized the mustang as a living symbol “of the historic and pioneer spirit of the West” that continues to contribute to the diversity of lifeforms within the United States and enrich the lives of Americans.

That spirit and the sense of animal union with man is still alive in the mustangs’ point of origin, the marshes of Doñana National Park in the western region of Andalusia, the southern portion of the Iberian peninsula that also embodies Seville.

The National Association of Cattle Breeders Marismeño in Spain was formed by descendants of people who, in ancient times, created a covenant between the god of the seas and horses, and now works to preserve the way of life for the last population of feral horses living in freedom.

In 2015, with the aid of the Association of Cattle Breeders Marismeño, photojournalist David Rengel documented the “La Saca de las Yeguas,” or “Out of the Mares” festival, an annual event that takes place in Andalusia in late June. The association’s efforts have been crucial toward the preservation of the Retuerta and Marismeño horses, two rare breeds that are some of the oldest in Europe and indigenous to Andalusia. Both have been placed on the endangered species list.

Each year, the horses make the sacred pilgrimage from Doñana National Park, considered the largest ecological reserve in Europe and declared a World Heritage Site by UNESCO in 1994, to the town of Almonte before being paraded through the village of Rocio, a world-famous center of pilgrimage. It is here where the horses’ life is blessed by a priest.

The horses of the Spanish marshes are descendants of the progenitors the of the mustangs in the United States and many domesticated horse herds in America. (David Rengel)

Mares are divided into separate pens where they will be held overnight. (David Rengel)

The Retuerta and Marismeño are two species in danger of extinction. Here a mare rests as the sun rises. (David Rengel)

A mare and a foal graze in the marshes of Doñana National Park, the largest nature reserve in Europe. (David Rengel)

A cattle breeder cares for a group of mares in one of the transits that takes place in February from Almonte to Doñana. During this time, mares will mate with stallions for new foals and preserve the species. (David Rengel)

The Marismeño horse is listed as a endangered species. Their hooves and legs are wide, facilitating transit through the wetlands. (David Rengel)

A breeder watches as another breeder rounds up the mares in the corral to divide them into different pens according to their owners. (David Rengel)

Francisco Javier Herrero Carmona, 18, was born in the village of El Rocio. For him, the horse breeding of the marsh is a way of life. (David Rengel)

During the festival on 26 of June, the horses are led from Doñana to Almonte, and cross the hermitage of Rocio, a world famous center of pilgrimage. (David Rengel)

A  mare rests after a hard day riding in the Doñana marshes. (David Rengel)