Heat a large pot over low heat. Cook sausage, stirring regularly, in the hot pot until completely browned, 10 to 15 minutes. Drain fat from sausage and return pot to heat.
Stir potatoes, celery, and onion into the sausage; cook, stirring often, until the potatoes are tender, about 30 minutes.
Preheat oven to 350 degrees F (175 degrees C).
Transfer sausage mixture to a large roasting pan. Beat eggs, marjoram, and parsley together; pour over the sausage mixture and stir. Fold bread cubes into the pork mixture. Cover pan with aluminum foil.
Roast in preheated oven for 45 minutes. Remove foil and continue baking until no longer moist on top, about 15 minutes more.