Preheat the oven to 325 degrees F. Remove the string tie, if necessary. If the pork roast has a thick fat cap, use a sharp knife to trim it down as much as you can without cutting away any of the meat. Then, place it fat cap side up, in a 6-quart Dutch oven.
In a small bowl, stir together the olive oil, Italian seasoning, rosemary, garlic, fennel seeds, salt, black pepper, and the crushed red pepper. Rub the mixture all over the roast.
Roast, covered for 3 hours. Remove the pot from the oven and add the diced tomatoes, mushrooms, and onion around the pork roast. Whisk together the wine and tomato paste and pour it over the pork (it’s thick so it will just coat the roast). Return the pot to the oven and roast, uncovered for 45 minutes to 1 hour more or until tender enough to shred.
Remove the roast from the pot and use two forks to coarsely shred the meat. Return the shredded meat to the pot. Alternately, just shred the pork directly into the sauce. Stir to coat and serve.