In a large sauté pan over medium-high heat, heat the olive oil. Add the onion and garlic, cook for 1 min., and then add the chicken. Cook, turning frequently, until the chicken is browned on all sides. Add the wine, vinegar, stock, oregano, and bay leaf. Cover the pan, reduce the heat to medium low, and simmer until the chicken feels firm and its juices run clear when pierced, about 30 minute Remove the chicken from the pan.
Bring the broth to a gentle boil, skim the surface, and cook until the sauce has reduced by one-third. Stir in the olives and anchovies. Add the parsley, salt, and pepper. To serve, pour the sauce over the chicken.