Preheat oven to 275 degrees F.
Blend together sage, rosemary, garlic, fennel seeds, salt, and pepper in a food processor until a thick paste forms. With motor running, add wine and oil and blend until combined well.
If necessary, trim fat from top of pork, to leave a 1/8-inch thick layer of fat. Make 3 small incisions, each about 1-inch long and 1-inch deep, in each side of pork with a small sharp knife, and fill each with about 1 teaspoon herb paste. Spread remaining herb paste over pork, concentrating on boned side, and tie roast with kitchen string at 2-inch intervals.
Put pork, fat side up, in a roasting pan and roast in middle of oven 6 hours. Transfer roast to cutting board and let stand 15 minutes. Discard string and cut pork roast (with an electric knife if you have one) into thick slices.
Cook's note: You can make the herb paste 1 day ahead and chill it, covered