Most popular of all Portuguese breeds, the Estrela Mountain Dog is also one of the oldest Molossers of the region. Believed to had been brought by either the Roman troops or the invading Visigoths to the Iberian Peninsula, this breed is closely related to the ancient eastern Molossers, like the Sarplaninac, Sylvan, Kangal and theCaucasian Ovcharka, as well as the Spanish Mastiff and the Portuguese Transmontano and Alentejo Mastiffs. The breed has traditionally been used as a livestock protector and valued for its strong defense drive and courage, with the organized working trials known as "concursos" reportedly being used to test the best examples for breeding selection, which served as the basis for the loosely set breed type of 1922. The first official breed Standard was written in 1933, with periodical alterations over the following years. The Estrela Mountain Dog has always been a working dog, but with the introduction of Shows, many old colourings have been seen as undesirable and have eventually vanished, but the overall physical appearance of the breed has changed relatively little since ancient times.
Named after the Estrela mountain region, it has been bred true to type for ages, up until the early decades of the 20th century, when the increasingly popular German Shepherd was introduced to its bloodline, although some pure strains survived in the remote rural areas. Seen by many as the worst episode in the breed's history, the first 40 years of the 20th century are referred to as the "Dark Ages for the Estrela" by some fanciers. After the WW2, the renewed interest in the working trials has helped revitalize the breed, but by the 1970's, the popularization of foreign dogs and the unfortunate decline in numbers of indigenous Portuguese breeds threatened to bring the Estrela Mountain Dog to extinction once again. Many credit the Portuguese Revolution of 1974 with saving this wonderful Molosser and thanks to a careful breeding programme conducted by dedicated breeders, the Cao da Serra da Estrela has been revived and is today back to its old self. The breed can today be seen in all parts of Portugal, as well as outside its native borders, slowly becoming a valued livestock guardian and property watchdog. Commonly encountered at Dog Shows, this handsome mountain dog is gaining popularity in many countries, including the United States, where the breed was recognized by the UKC in 1996 and the official Estrela club has been formed in 1998 to promote this great working dog and ensure proper breeding practices.
The Estrela Mountain Dog is an alert and dedicated guardian, often seen patroling the property in search of intruders, rather than calmly waiting for them. An excellent sheepdog, it has reportedly also been used in the past as a cart-pulling dog, as well as a capable wolf killer. It makes an impressive service dog, commonly employed by the Portuguese Police. Aggressive towards threatening strangers, the Estrela is much more relaxed when away from its territory, while remaining alert and focused. Gentle with children and devoted to its owner, it can be a very good family dog, although it prefers living outside. This is an athletic breed, known for its great speed and remarkable agility. Intelligent and independent, the Estrela is a reasonably easy dog to train, but it can be quite stubborn at times, needing early socialization and experienced handling. Due to its protective drive and dominant nature, this Moloss requires responsible supervision around strange dogs. This rustic breed comes in two main varieties, the popular Northern-Estrela long-coat and the less commonly found Southern-Estrela short-coat type. Reportedly, there is also another Estrela variant, the much larger, heavier, long-coated "old mountain" type, but it allows for a greater number of colour variations, preventing that type from being accepted into the modern Estrela categorization. The Cao da Serra da Estrela belongs to the lighter group of Molossian mastiffs, having a powerful and compact body, but also a perfectly balanced head-type posessing both the lupoid and molossoid facial features.
The coat comes in solid colours of fawn, yellow, wolf-gray, brown, black and brindle with or without small white markings and usually a very dark face mask, but the classic fawn is preferred for show, while the rarely seen piebald examples aren't accepted. Average height is around 28 inches, although slightly smaller examples exist.