Italian Potato Casserole

1 pound potatoes, peeled
4 tablespoons olive oil
1 onion, thinly sliced
2 teaspoons chopped garlic
1 cup pitted green olives
1 pound canned chopped tomatoes
1 tablespoon chopped fresh majoram
salt and pepper to taste

Cut the potatoes into 1-2 inch chunks. Heat the oil over a low heat. Turn heat up to medium and add the potatoes, onion, garlic and olive. Cook about 3 minutes. Stir in the tomatoes, marjoram, salt and pepper. Reduce heat to low and cook about 30 minutes. Potatoes should be tender.