Rinse turkey and pat dry.
In a shallow bowl, mix flour, salt, oregano and pepper.
Dust turkey with flour mixture; set remaining flour mixture aside.
Heat oil in a wide frying pan over medium heat. Add turkey, a few pieces at a time (do not crowd pan); cook, turning as needed, until browned on all sides. Transfer to a 4 to 6-quart baking pan.
Add onions and garlic to frying pan; cook, stirring often, until onions are soft, about 5 minutes.
Add broth and wine, stirring to scrape browned bits free. Then add bay leaf, thyme and rosemary.
Pour broth mixture over turkey, cover, and bake in a 350*F (175*C) oven until turkey is very tender when pierced, about 2 to 2 1/2 hours.
Lift turkey from baking pan and arrange in a serving dish.
Measure reserved flour mixture and blend with an equal amount of cold water; stir into pan juices. Cook, stirring, until sauce boils and thickens.
Spoon some of the sauce over turkey; pour remainder in a small serving dish and offer to spoon over individual servings.