In the Italian peninsula leucite-free and -bearing ultrapotassic rocks occur intimately associated but well separated in time. Silica-saturated ultrapotassic and associated shoshonitic magmas erupted during the Pliocene to Lower Pleistocene. Silica under-saturated leucite-bearing ultrapotassic rocks, mainly leucitites, were emplaced sometime later, during the Middle–Upper Pleistocene. The transition from leucite-free to -bearing rocks is diachronous and in some cases is complicated by the occurrence of crustal-derived magmas coeval with early leucite-free magma.