In a large bowl, stir together garlic, oregano, vinegar, prunes, olives, capers, salt and pepper, bay leaf, brown sugar and wine. Add the chicken pieces and stir to coat. Cover and let marinat, refrigerated, overnight.
Place the chicken in slow cooker, then pour marinade over it. Set to high heat and cook for about 5-6 hours, or until chicken is tender.
Transfer chciken to a serving platter and spoon sauce over it. Sprinkle with parsley and cilantro.