Remove tomatoes from can, reserving the juice. Using your hands, crush the tomatoes, gently remove and discard the hard core from the stem, and remove any skin and tough membrane. Set aside tomatoes.
In a large nonreactive pot over medium heat, add oil and heat. If using fatback, cut it into small pieces and add to the pan. Saute for 5 minutes or until all fat has been rendered. Remove and discard fatback.
Add the onion, and saute for 3 minutes or until translucent, and just becoming brown. Stir in garlic, and saute for 30 seconds or until soft. Stir in tomatoes, reserved juice, and salt. Raise heat, and bring to a boil. Immediately reduce heat to a very low simmer and cook for about 1 hour, or until flavors have combined and sauce is slightly thickened. If you prefer a thicker sauce, cook for an additional 15 minutes.
Stir in basil, oregano, pepper, and allow to cook for an additional minute. Remove from heat and serve.