Place lemon inside chicken. Chop enough thyme for 2 teaspoons. Reserve remainder for garnish. Mix 1 teaspoon chopped thyme, 2 teaspoons oil, 1/4 teaspoon salt and 1/4 teaspoon pepper. Rub over chicken. Place in large roasting pan.
Combine potatoes, onion, garlic, olives, remaining chopped thyme, remaining oil, salt and pepper. Arrange potatoes around chicken.
Roast in 400 degree F oven 1 hour. Add tomatoes. Roast 15 minutes until chicken is no longer pink. Arrange on platter. Garnish with thyme sprigs. Makes 8 servings.