Slice the veal into eight thin cutlets. Each piece should be about 1/4 inch thick.
Place the veal slices on a flat work surface and use a meat mallet, tenderizer, or rolling pin to pound them thinner and make the meat soft.
Place one slice of prosciutto on top of each piece of veal then top each with one sage leaf. Use a toothpick to secure the veal, prosciutto, and sage together.
Add the olive oil to a large skillet and heat over medium-high heat.
Dredge the veal in the flour, coating only the bottom side of the veal with the flour (not the top portion with the sage and prosciutto). Shake off any excess flour then place the floured veal directly into the shimmering oil with the sage leaf side facing up.
Sear the saltimbocca for about 3-4 minutes so the bottom is golden brown.
Sprinkle the ground black pepper and salt over the veal in the skillet.
Pour the wine into the skillet and cook for 2 minutes.
Remove the veal from the skillet and set aside on a dish.
Add the butter to the same pan along with water. Use a wooden spoon to scrape the browned veal and flour off the bottom of the pan then whisk it into the sauce. Simmer the sauce until it begins to thicken.
Spread the sauce on the bottom of a warm plate or serving plate then place the cooked saltimbocca alla romana on top. Enjoy while hot!