The history of Cres really starts with the Illyrian tribe the Liburni who created a number of settlements on the island before the Romans invaded in the 2nd century AD. Cres, Osor and Beli (where the griffon vulture sanctuary, Caput Insulae, is now located) were all important settlements during Roman times.
Cres and and the neighbouring island of Losinj used to be one large island, before being divided by a channel that was dug in Roman times so boats could sail between the two. (Unlike then, there is now a bridge that connects the two islands so it is easy to travel from one to the other.)
After Croats took control in the 10th century, the island fell to the Venetian Empire, firstly from 1000 to 1358 and after a brief stretch of rule by the Croatian-Hungarians, again until 1797.
As with much of the surrounding area, Cres also became part of the Austro-Hungarian Empire in 1814.
After World War I, the islands became part of Italy, with this agreement strengthened by the 1920 Treaty of Rapallo. After World War II (in 1947, in fact), the island was returned to Yugoslavia and was of course part of Croatia when the country declared its independence in 1991.