Cut the chicken up into serving pieces of roughly equal size. Dry all the pieces thoroughly with paper towels and set aside.

In a braiser or sauté pan large enough to hold all the chicken pieces in one layer, sauté the garlic cloves in abundant olive oil over moderate heat for just a minute or two, until you can smell the aroma and the garlic is starting to brown lightly. Remove the garlic and add the chicken pieces. Brown them lightly but thoroughly on all sides, seasoning with salt and pepper as you go. 

Pour on a splash of white wine and tomatoes purée and cover the pan, leaving the lid slightly ajar. Simmer gently about 30-45 minutes, or until the chicken is tender and cooked through, turning the chicken pieces at least once. Add water if needed to keep things moist and, about halfway through, the rosemary leaves. By the time the chicken is cooked, the pan juices should be well reduced; if not, continue simmering uncovered for a few minutes. 

Serve the chicken hot, napped with the pan juices.