The Leonberger started in the 1830s as a cross between a Newfoundland dog and a Saint Bernard. The Great Pyr added later. The best descriptions are available here:
Leos are a very attractive breed and people will often come up and ask about your dog. They aren't very common so you'll get a lot of questions about them while walking down the street. In some cases, walks take longer than you expect because you get stopped so often! They have a lot of personality and really just love being with their people.
Do they drool?
No, but when they drink there's a 2-foot splash radius.
Do they shed?
Yes, but not as bad as you'd think. They blow their coats a couple of times per year, but other than that they don't shed a lot on a regular basis.
How big do they get?
Males can be over 150 lbs, females tend to be in the 100 lbs - 120 lbs range.
Where do they sleep?
Anywhere they want 🙂 But they prefer cold floors like the ceramic tile in the porch.