Before the East-West Schism, the Grikos were Catholics who adhered to the Byzantine Rite.
 Some Greeks of Southern Italy managed to rise to positions of power in the Church, like Pope John VII and Antipope John XVI.
In the 11th century the Normans overran southern Italy, and soon Bari, the last Byzantine outpost, fell to them.
They began a process of Latinization.
The Greek clergy eventually adopted Latin for the Mass, although Greek resistance to the Latin rite was prolonged in Calabria.
Latin prelates were not established at Cosenza, Bisignano and Squillace until 1093-6.
In 1093 the Norman King Roger attempted to install a Latin archbishop over the overwhelmingly Greek population of Rossano, however this was a complete failure, a revolt took place in favour of restoring the Byzantine rite.
At Crotone, Bova, and Gerace the clergy continued to use the Greek liturgy even though they were under Latin bishops.
In Apulia, where the Normans took a less intense attitude to the Latinisation of the people, the Griko people continued to speak the Greek language and to celebrate the Byzantine rite.
Some Griko in both Calabria and Apulia remained adherents to the Byzantine rite until the early 17th century.
Today, the Griko people are mostly Catholics who adhere to the Latin Rite.
Before the East-West Schism, the Grikos were Catholics who adhered to the Byzantine Rite.  Some Greeks of Southern Italy managed to rise to positions of power in the Church, like Pope John VII and Antipope John XVI. In the 11th century the Normans overran southern Italy, and soon Bari, the last Byzantine outpost, fell to them. They began a process of Latinization. The Greek clergy eventually adopted Latin for the Mass, although Greek resistance to the Latin rite was prolonged in Calabria. Latin prelates were not established at Cosenza, Bisignano and Squillace until 1093-6. In 1093 the Norman King Roger attempted to install a Latin archbishop over the overwhelmingly Greek population of Rossano, however this was a complete failure, a revolt took place in favour of restoring the Byzantine rite. At Crotone, Bova, and Gerace the clergy continued to use the Greek liturgy even though they were under Latin bishops. In Apulia, where the Normans took a less intense attitude to the Latinisation of the people, the Griko people continued to speak the Greek language and to celebrate the Byzantine rite. Some Griko in both Calabria and Apulia remained adherents to the Byzantine rite until the early 17th century. Today, the Griko people are mostly Catholics who adhere to the Latin Rite.
Griko people