Combine the red wine, tomato paste, thyme, marjoram, and red wine vinegar in a bowl.
Season each chicken piece with sea salt and black pepper to taste.
Place the chicken in a marinating dish (glass or plastic no metal) with the wine mixture and marinate for at least 30 min.
Preheat your oven to 400 F.
Place the onions, carrots, and sweet potatoes in a baking dish, and pour ¼ cup of water over them.
Remove the chicken from the marinade and arrange the pieces, skin side up, on top of the vegetables.
Pour the remaining marinade over the chicken and vegetables.
Cover the whole pan with foil and roast in the oven for 30 minutes.
Remove the foil and roast, uncovered, for another 30 to 45 minutes, basting every 15 minutes.