After the Battle of Taginae, in which the Ostrogoth king Totila was killed, the Byzantine general Narses captured Rome and besieged Cumae. Teia, the new Ostrogothic king, gathered the remnants of the Ostrogothic army and marched to relieve the siege, but in October 552 Narses ambushed him at Mons Lactarius (modern Monti Lattari) in Campania, near Mount Vesuvius and Nuceria Alfaterna. The battle lasted two days and Teia was killed in the fighting. Ostrogothic power in Italy was eliminated, but according to Roman historian Procopius of Caesarea, Narses allowed the Ostrogothic population and their Rugian allies to live peacefully in Italy under Roman sovereignty. The absence of any real authority in Italy immediately after the battle led to an invasion by the Franks and Alemanni, but they too were defeated in the battle of the Volturnus and the peninsula was, for a short time, reintegrated into the empire.
The Kings of the Lombards (Latin: reges Langobardorum, singular rex Langobardorum) ruled that Germanic people from their invasion of Italy in 567–68 until the Lombardic identity became lost in the ninth and tenth centuries. After 568, the Lombard kings sometimes styled themselves Kings of Italy (Latin: rex totius Italiæ). Upon the Lombard defeat at the 774 Siege of Pavia, the kingdom came under the Frankish domination of Charlemagne. The Iron Crown of Lombardy (Corona Ferrea) was used for the coronation of the Lombard kings, and the kings of Italy thereafter, for centuries.
The primary sources for the Lombard kings before the Frankish conquest are the anonymous 7th-century Origo Gentis Langobardorum and the 8th-century Historia Langobardorum of Paul the Deacon. The earliest kings (the pre-Lethings) listed in the Origo are almost certainly legendary. They purportedly reigned during the Migration Period; the first ruler attested independently of Lombard tradition is Tato.
The actual control of the sovereigns of both the major areas that constitute the kingdom – Langobardia Major in the centre-north (in turn divided into a western, or Neustria, and one eastern, or Austria and Tuskia) and Langobardia Minor in the centre-south, was not constant during the two centuries of life of the kingdom. An initial phase of strong autonomy of the many constituent duchies developed over time with growing regal authority, even if the dukes' desires for autonomy were never fully achieved.
The Lombard kingdom proved to be more stable than its Ostrogothic predecessor, but in 774, on the pretext of defending the Papacy, it was conquered by the Franks under Charlemagne. They kept the Italo-Lombard realm separate from their own, but the kingdom shared in all the partitions, divisions, civil wars, and succession crises of the Carolingian Empire of which it became a part until, by the end of the ninth century, the Italian kingdom was an independent, but highly decentralised, state.