Cannonau di Sardegna is a red wine grape varietal from the island of Sardegna. Cannonau is thought to be the grape known as Grenache/ Garnacha. It is the mostly widely planted grape varietal on the whole island as well as one of the most planted varietals worldwide.

Common thought is that the variety arrived on Sardegna with the Aragonese when they conquered the island in the early 14th Century (from what is now Aragon).
Cannonau Grapes

However, in the past few years researchers have discovered (during an Archeological Dig in Sardegna) Cannonau seeds which date back to pre roman times therefore it is entirely possible that the Cannonau Grape (aka Grenache/ Garnacha) actually originated on the Island of Sardegna. Cannonau is used to produce Red, Rose as well as fortified Dessert Wines