Add the garlic, onion and ground fennel to the casserole and cook over moderately low heat, stirring occasionally, until the onion is softened, about 10 minutes. Add the tomato paste and cook over moderate heat, stirring, until glossy, about 2 minutes. Add the wine and simmer for 2 minutes. Stir in the stock and bring to a boil. Return the pork to the casserole and add the carrots, olives, thyme, bay leaves, rosemary and the tomatoes with their juices. Cover tightly and simmer over low heat, stirring a few times, until the pork is tender, about 2 1/2 hours. Discard the herb sprigs and bay leaves. Season the stew with salt and pepper and serve.