Ratchis († after 757) was the Duke of Friuli (739–744) and King of the Lombards (744–749).
The Kingdom of the Lombards played a major role in early Venetian history, as it was the Lombard invasion of Italy in 568 which started the formation of later Venice.
The “Historia Langobardorum” is the oldest chronicle relevant to the history of Venice. It probably dates to the 780s or 790s.