Salve!
Although I have grown up in the US, I was born in Sardinia (I am a naturalized US citizen, adopted by American parents). Sardinia became part of the Roman "Republic" after the First Punic War (see the summary elsewhere on this site). Sardinia was settled by Carthaginians along its coast. There have been speculation that Rome attempted to place a colony in the mid-4th century, according to Ptolemy's geography (scholars today dispute that for the most part, as no other evidence exists). What is more clear is that once Rome held Sardinia, it faced the fun of putting down several revolts during the 3rd century (Manlius Torquatus) and 2nd century (Ti. Sempronius Gracchus, and M Caecilius Metellus). Despite all that, Sardinia was one of the mainstays of Rome's needed grain supply, even according to Cicero. At least, that is, until Octavian conquered Egypt.
(Historical material comes from Dyson & Rowland's Shepherds, Sailors and Conquerors: Archaeology and History in Sardinia