Combine the flour, salt and pepper in a plastic bag. Shake the chicken pieces in flour until coated. Heat the oil in a large frypan (one that has a cover/lid). Fry the chicken pieces until they are browned on all sides. Remove from frypan.
Add the onion, garlic and capsicum to the frypan and saute until the onion is slightly browned. Return the chicken to the frypan and add the tomatoes, oregano and wine. Cover and simmer for 30 minutes over medium low heat.
Add the mushrooms and salt and pepper to taste. Simmer for 10 more minutes.