The reign of Liutprand, son of Ansprand, duke of Asti and briefly king of the Lombards, began the day before his father's death when magnates called to Ansprand's deathbed consented to make Liutprand his colleague. Liutprand's reign endured for thirty-one years. Within the Lombard kingdom he was considered a lawgiver of irreproachable Catholicity.
Relations with the Agilolfings of Bavaria
At the opening of his reign, Liutprand's chief ally among neighboring rulers was the Agilolfing Theodo I, the Frankish duke of Bavaria. Theodo I's intervention on Ansprand's behalf helped him gain the throne. Theodo had taken him in, when he and his father were temporarily expelled by Aripert II in 702, and the hospitality was later cemented with a marriage connection: Liutprand took to wife the Agilolfing Guntrud. The core of Theodo's policy was resistance to the Merovingian mayors of the palaces in their encroachments north of the Alps, concerns that did not much occupy Liutprand, and maintaining strategic control of the eastern Alpine passes in what is now the Italian Alps, which did. In the spring of 712, Theodo’s son Theodebert, with Ansprand and Liutprand, attacked Lombard strongholds, and with the drowning of their fleeing rival Aripert, Ansprand's faction were back in power at Pavia.
Theodo died in 717 or 718; under his successor the Lombard ties with the Agilolfing weakened. Until distracted by Byzantine politics in 726, Liutprand's chief warmaking energies were concentrated on taking Bavarian castles on the River Adige.
Italy after the conquests of Liutprand. Lombard territory shown in green, Byzantine territory in orange.
In his early reign, Liutprand did not attack the Exarchate of Ravenna or the Papacy. But in 726, the Emperor Leo III made his first of many edicts outlawing images or icons (see the iconoclastic controversy). The pope, Gregory II, ordered the people to resist and the Byzantine duke of Naples, Exhiliratus, was killed by a mob while trying to carry out the imperial command to destroy all the icons. Liutprand chose this time of division to strike the Byzantine possessions in Emilia. In 727, he crossed the Po and took Bologna, Osimo, Rimini and Ancona, along with the other cities of Emilia and the Pentapolis. He took Classis, the seaport of Ravenna, but could not take Ravenna itself from the exarch Paul. Paul was soon killed in a riot, however. Eventually, Ravenna would capitulate to Liutprand with barely a fight (737).
The first Moorish raids on Corsica began around 713–719 from the Balearic Islands to the west. Acting as the protector of the Catholic Church and its faithful, Liutprand subjected the island to Lombard government (c. 725), though it was nominally under Byzantine authority. Corsica remained with the Lombard kingdom even after the Frankish conquest, by which time Lombard landholders and churches had established a significant presence on the island.
When the Saracens invaded Sardinia, Liutprand redeemed the body of Augustine about the year 720. He brought it with great ceremony to Pavia, and enshrined it in the Church of Saint Peter, which was then the cathedral of Pavia. He rescued the relics stationed on the island with great haste as well as with great expense, according to Paul the Deacon.
Donation of Sutri
Having just overwhelmed the Byzantine forces, though it was left to his heirs to make the final vestige of the Exarchate of Ravenna Lombard at last, Liutprand advanced towards Rome along the Via Cassia; he was met at the ancient city of Sutri by Pope Gregory II (728). There the two reached an agreement, by which Sutri and some hill towns in Latium (see Vetralla) were given to the Papacy, "as a gift to the blessed Apostles Peter and Paul" according to the Liber Pontificalis. They were the first extension of Papal territory beyond the confines of the Duchy of Rome. This was the beginning of the Papal States.
In the meantime, Leo sent Eutychius, as Exarch of Ravenna, to take control of Italy. When Eutychius arrived at Naples, he made an agreement whereby Liutprand would attack the Pope if the Greeks aided him in subjugating the contumacious and independent southern Lombard duchies, the Duchy of Spoleto and the Duchy of Benevento. The dukes, Thrasimund II and Godescalc, surrendered — though control of the duchies from Pavia was not to endure for long — and the new exarch marched on  and arbitrated, returning to the exarch the city of Ravenna alone among the Byzantine territories and prevailing on the pope to restore his allegiance to the emperor (730).
So-called "Pilatus' basin", in the middle of the so-called "Pilatus' Courtyard" of Santo Stefano
. This eighth-century Lombard sculpture bears the names of kings Liutprand and Ilprand
, as well as of the bishop
Following the death of Theodo, Liutprand turned from his former Agilolfing allies to bind himself to Charles Martel, duke of the Franks, whose son, Pepin the Short, he adopted and girded with arms at his coming of manhood. In 733 Liutprand promulgated the Notitia de actoribus regis, a series of six laws, presaging the later Frankish capitulary in structure. They sought to curb the usurpation by local administrators of public lands.
In 735–736, a serious illness encouraged Liutprand to raise his nephew Hildeprand to co-kingship. In 736–737, Liutprand crossed the Alps with an army to help Charles expel the Moors from Aix-en-Provence and Arles.
In 738, a long peace was broken by the rebellious Lombard duke of Spoleto, Thrasimund II. When the revolt was suppressed, with nephews of Liutprand established at Beneventum and Spoleto, the dukes fled to Rome and the protection of Pope Gregory III. Liutprand immediately began the conquest of the Ducatus Romanus, the province around Rome. After capturing Orte and Bomarzo, he arrived at Rome and besieged it. The Pope sent an embassy to Charles Martel to beg for aid, promising favour then and in the future world: the cover letter survives. Gregory conferred on him the title of patrician. Gregory's anti-Lombard rhetoric reached absurd heights considering Liutprand's orthodoxy; the Lombard king only wanted his rebellious dukes to face justice. Charles ignored the pope's excessive charges against his erstwhile ally and instead sent back his own embassy to mediate between the two Italian powers. Before any headway was made, however, both pope and Frank died.
Soon after the death of Gregory III (741), Zachary was elected to the Apostolic See; Liutprand happily signed a twenty-year peace and restored the cities of the Duchy of Rome of which he had taken possession. Soon after, his reign ended in peace. Having passed more years on the throne and come closer to bringing the entire peninsula under one rule than any of his predecessors, the great Lombard died in 744 and was buried in the church of San Pietro in Ciel d'Oro, in Pavia.