Formerly called Rosito, it takes its name from the abundance of wild roses in its territory. The addition of Valfortore refers to the Fortore River, which has its source to the east of the town and flows through the valley.
I century A.D., a tombstone in Latin testifies to the presence of Roman civilisation.
752, the name 'Rosito' appears for the first time in the document in which the Lombard duke Liutprand decrees freedom for the slave girl Cunda and her son Liupergo.
1122, after having belonged under Norman rule to the County of Ariano, Roseto passed to William Guiscard, Duke of Apulia, following a successful assault.
1294, Bartolomeo I Di Capua took over the fief of Roseto in place of D'Assimial, who had received it from Charles of Anjou after the capture of Lucera.
1338, the fief of Roseto with that of Vetruscelli is assigned to Roberto Di Capua.
1497, Bartholomew III, having received feudal confirmation from the King of Naples, Ferdinand the Catholic, brought the village to its greatest splendour. The decline began with Giovanni, the last of the Di Capua family, who sold Roseto to Ferrante Lombardo di Troia.
1640, the feud passed from the Lombardos to the Brancias.
1655, Giuseppe Saggese of Foggia bought the fief that remained in his family until the early 19th century.
1848, Roseto actively participated in the Risorgimento uprisings and then experienced Garibaldi's adventure with bloodshed.
1882, the exodus to the USA began, where in 1912, emigrants from Roseto, Pennsylvania, established a new town across the ocean, making it one of the Municipalities of America.
1946, after the Second World War, migration resumes, this time to Canada. Roseto depopulates: from 5400 inhabitants in 1946, it passes to 1300 today.