Heat the oven to 425°F. Season the chicken inside and out with salt and pepper. Using a mini food processor, a mortar and pestle, or a knife, mash together the marjoram, thyme, garlic, and 1 Tbs. of the olive oil to form a rough paste.
Slide your fingers between the chicken's skin and flesh to loosen the skin on the breast, thigh, and leg areas. Rub the herb paste onto the flesh under the skin so it's distributed as evenly as possible. Put half of the lemon slices, half of the olives, and one-third of the mushrooms in the cavity. Truss the bird, if you like, and put it, breast side up, in an enameled cast-iron pot or a Dutch oven. Drain the sun-dried tomatoes and arrange them around the chicken. Scatter the onion pieces and the remaining lemon slices, olives, and mushrooms around the chicken as well. Pour the white wine and the remaining 1/4 cup olive oil over the vegetables around the chicken. Roast, basting every 10 min. or so with the pan juices, until an instant-read thermometer in the thigh meat reads 170°F or the juices run clear, 1 to 1-1/4 hours; the vegetables should be tender.
To serve, set the chicken on a carving board and spoon out the vegetables from the cavity. Defat the pan juices and serve as a sauce, if you like. Remove any trussing, carve the bird, and serve on a platter with the lemons, olives, mushrooms, onions, and tomatoes arranged around the chicken.