LAMB AND SEASONING: Place racks in middle and bottom positions in oven; preheat oven to 450. Place lamb on rack in large roasting pan. Combine oil, rosemary, garlic, salt and pepper; rub paste over lamb. Roast on middle oven rack 15 minutes. COMPOTE: Meanwhile, in medium roasting pan, combine tomatoes, onion, 2 tablespoons if the oil, the garlic, and pepper; place on bottom oven rack. Reduce temperature to 350. Roast lamb and tomato mixture, roasting lamb pan and stirring tomatoes once, 1 1/2 hours or until internal temperature of thickest part of lamb registers 145 on instant-read thermometer for medium-rare (shank end will be medium). Transfer lamb to cutting board; tent loosely with foil; let stand 15 minutes; carve. Into tomato mixture, stir remaining oil, the olives, sugar, vinegar and capers. Serve with the lamb. Makes 8 servings.