He was a son of the duke Pemmo [Pemmone] and brother of Aistulf, and when around the year 738 he replaced his father, he became duke of Friuli, in his turn. Indeed Pemmo [Pemmone] had been dismissed by king Liutprand after a contrast occurred with patriarch Callistus. Ratchis, who had been brought up at the Lombard court, defined Liutprand as his “nutritor”. At Cividale Ratchis kept on his father’s work and committed the altar that bears his name and is considered one of the most outstanding monuments of the Lombard art. Among other things the altar inscription makes reference to the engagement Pemmo [Pemmone] lavished on restoring the religious buildings of the ducal city. After Liutprand’s death in 744, his nephew Hildeprand succeeded to the throne he had been earlier associated to, yet after only eight months he was set back and replaced by Ratchis. The latter had been able to gain the pope’s support with whom, perhaps by urging of his wife, the Roman noble Tassia, he ratified a twenty-year peace which had as a consequence the sharpening of the formerly strained relations with the more traditionalist milieus who withstood any form of opening to a Romanesque majority. This opponent faction, which did not approve the Lombard people’s progressive approach to the mass of Roman subjects and was against any compromise with the papacy, compelled the king to undertake a conquering campaign. After long negotiations the pope could convince Ratchis to desist, but his opponents availed themselves of this opportunity to depose the sovereign whose authority proved to be definitely spoiled and in 749, at Milan, they elected his brother Aistulf as king of the Lombards. Ratchis chose to enter monastic life and retired to Montecassino. In 756, after Aistulf’s death, a new possibility appeared to Ratchis to come to the throne again, but after a few months he was defeated by Desiderius. Ratchis’ deposition was the consequence of the stronger position of the faction that was more favourable to restart war, as well as of the fact that he, as a monk, could no longer hope to reign over his people.
For further information see the entry Ratchis, duca del Friuli e re dei Longobardi written by Massimo Dissaderi in Nuovo Liruti. Dizionario biografico dei Friulani, 1, Il Medioevo, edited by C. Scalon, Udine, Forum, 2006, 725-728.