From the website of the International Union for Leonbergers
The Leonberger is a dog of impressive size and elegant appearance. Although the population of many breeds was decimated during World War I, today the breed has recovered nicely. The breed is well known in several European countries, but in many countries of the world is still considered a rare breed.
The Leonberger is a giant breed, with a distinct sexual dimorphism. Females are 65-75 cm (25.5 – 29.5″) tall and weigh about 48 kg (105 pounds). Males are 72-80 cm (28 – 31.5″) tall with an average weight of over 60 kg (132 lbs). They are double coated and come in many shades of brown (from a sand color to dark reddish brown) and often have black tips on their guard hairs. Their most distinguishing feature is a black facial mask. Leonbergers should be a dog with good substance, yet have elegant movement and a gentle nature.
The Leonberger is classified by the FCI in the molossians, type mountain dog (Group 2, Section 2.2). The Leonberger is not a typical working breed that was bred to serve one purpose. Today’s Leonberger is best described as a family companion who takes the “work” of making certain his human family is not lonely. While not the best choice for a running or bicycling companion, Leonbergers do enjoy hiking, swimming and gatherings of family and friends. Leonbergers can be trained to do almost anything as long as you have patience and a sense of humor! Leonbergers have captured working titles in obedience, water rescue, agility, carting and herding and seem to have a natural ability as therapy dogs. They are happiest as a member of a family that includes the Leonberger in daily activities.
Guido Perosino, the founder of the Italian Leonberger club, notes in his 1998 book, The Leonberger:
“. . . the most interesting characteristic of the Leonberger is his lack of specialization. Although his is the body, the strength and the muscle of a typical working dog, the fact that he has been selectively bred for the balanced temperament of a house dog. . rather than for any precise working task, has gifted him with a versatility almost unique on the present canine scene. The Leonberger adapts himself well and often spontaneously to various uses; he seems to know instinctively what is expected of him.”
While not the perfect dog for everyone, they are a true mix of canine strength and elegance at its best.