Val Demone or Val di Demona (English: 'Valley of Demona') is a historical and geographical region encompassing the north-eastern third of Sicily. Historically, it was one of the three valli of Sicily.
Val Demone was the last part of the island to be conquered by the Arabs in the 10th century. Christian refugees from other parts of Sicily congregated there, and the region remained in contact with the Byzantine provinces in southern Italy. It was the base for the Byzantine attempt to reconquer Sicily under George Maniakes in the early 11th century. Consequently it was the least Arabicized and Islamicized part of Sicily, and was still mostly Greek-speaking at the time of the Norman conquest in the 11th century.
- Metcalfe (2009), pp. 34–36, 40
- Loud, G. A. (2007). The Latin Church in Norman Italy. Cambridge University Press. p. 494. ISBN 978-0-521-25551-6.
At the end of the twelfth century ... While in Apulia Greeks were in a majority – and indeed present in any numbers at all – only in the Salento peninsula in the extreme south, at the time of the conquest they had an overwhelming preponderance in Lucaina and central and southern Calabria, as well as comprising anything up to a third of the population of Sicily, concentrated especially in the north-east of the island, the Val Demone.