Finely chop 2 garlic cloves and combine them in a large bowl with 1 tablespoon olive oil, 1 tablespoon of the dried rosemary and/or oregano, juice of 2 lemons, and dry red wine to make a marinade. Marinate lamb in mixture, cover and refrigerate for 6 to 12 hours, turning lamb several times.
Remove lamb from refrigerator. Preheat over to 450 degrees F and lightly oil a large baking pan.
With a mortal and pestle, crush together all but 1 of the remaining garlic cloves and remaining herbs. Remove lamb from marinade and reserve liquids. With a sharp knife, make 3/4 inch slits all around leg of lamb and stuff garlic and herb mixture inside slits. Reserve a small amount of the mixture for step 4.
Rub lamb with olive oil and 1 whole garlic clove, salt, pepper, and remaining herb mixture. Place lamb in prepared baking pan and arrange potatoes around it, if desired. Season potatoes with salt, pepper, and juice of remaining 2 lemons. Pour marinade over lamb. Place uncovered in oven and reduce heat immediately to 350 degrees F. Bake for about 30 minutes per pound, or until lamb is tender and slightly rare, and potatoes, fork tender. Baste ever 10-15 minutes with pan juice. If potatoes need more liquid, add a little water to the pan before cooking.