Toss potatoes and 2 sliced onions with rosemary and olive oil in a large bowl. Season to taste with salt and pepper; spread into a large, shallow baking dish.
Bake potatoes in the preheated oven until tender, about 45 minutes.
Meanwhile, heat olive oil in a large frying pan over high heat. Cook rabbit pieces, turning once, until brown on both sides, about 10 minutes. Add the remaining onion, olives, sage and marjoram and cook for 2 minutes. Reduce heat to medium-low, cover and simmer for 30 minutes.
Stir artichokes, tomato puree and parsley into frying pan with rabbit. Replace lid and simmer until artichokes are tender, about 15 minutes. Serve with rosemary potatoes.