Krk has for many years been thought the largest Adriatic island, with an area of , although recent measurements now give the neighbouring island of Cres an equal surface area. Krk is also the most populous island, with numerous towns and villages totalling 19,286 (2011).
Archeological finds show that the island has been inhabited without interruption since the Neolithic age. According to Greek and Latin sources, Curicta, Κύριστα in ancient greek (Krk) is one of the Apsyrtidian or Electridian islands held by the Liburnians. There are the remains of prehistoric settlements near Draga Bašćanska and Bronze Age and Iron age earthworks near Malinska, Dobrinj, Vrbnik and Baška.
Krk came under the Romans once they had defeated the Liburnians. The Town of Krk (Curicum) became a town with Italic law whose status evolved to give it the rights of a municipality. Nothing is known about the internal organisations of the town of Krk from this time. Near the present day Franciscan monastery the remains of thermal baths have been found. The defensive walls of Roman Curicum were amongs the most secure of all the towns on the Eastern Adriatic fortified by the Romans. Work began on their construction during the Civil War in Rome (50 BC) and they were further strengthened in the 60s of the 2nd century AD, to enable them to withstand attacks by the Quadi and the Marcamanni who were at that time threatening the Adriatic. Not far from Krk in 49 BC there was a decisive sea battle between Caesar and Pompey, which was described impressively by the Roman writer Lucan (AD 39–65) in his work Pharsalia. When the Empire was divided, Krk came under the Eastern Roman Empire.
Migrations of the nations
The walls of the town of Krk could not withstand attacks by the Avars (7th century), but in contrast to Salona, Scardona and Aeona, life in Krk quickly returned to normal. The Slavs penetrated into the town on several occasions. They retained many of the Roman names they found there arid so it is said that Krk has a "mosaic dialect". Following the Treaty of Aachen (812) the entire island was ceded to the Byzantine Empire and was governed according to the norms of that Empire. During the reign of Emperor Constantine Porphyrogenitus (10th century), Krk was known as Vekla, of which the Romanized variant, also used by the Venetians, was "Veglia".
Time of the Croatian Counts and Kings
There are no extant documents showing when Krk became part of the Croatian state. It is known that from around 875 the Byzantine town paid the Croatian rulers 110 gold pieces a year to be able peacefully to keep their hold there. It is also disputable that Krk was under the Croatian kings during the reign of King Zvonimir. While the Croatian state was being established, Krk found itself on the Venetians' route to the Mediterranean. The Venetians conquered the town for the first time in 1001, and from then Krk's history was closely linked with the history of the Republic of Venice for seven centuries. During the reign of Peter Krešimir IV the Croatian rulers regained their power, but the Venetians took Krk for the second time in 1118.
Reign of the Krk Counts (from 1430, the Frankopan family)
When the Venetians conquered Krk for the second time in 1118, the local noble family, the unknown Dujams, received Krk as part of a pact with Venice, and they became Counts. When Dujam died in 1163, Venice allowed his sons to make their position hereditary, after a payment of 350 Byzantine gold pieces as tax. In a short time the Krk Counts became so strong that at one time from 1244 to 1260, Venice rescinded their authority. This failed to impede their rise however. They increased economic exploitation, but they also endeavoured to strengthen old traditions and rights with various statutes (the Vinodol Code 1288 and the Vrbnik Statute, 1388). Dujam's youngest son, who died in 1209, succeeded in extending his authority to the mainland, began to serve the Croatian-Hungarian King and received the district of Modruš. Due to his economic strength and social standing, his opponents fought each other for his favour. The Counts became so strong that no power could threaten them (until the Turks). Members of his family were leaders in Split, Trogir and Senj, and from 1392 one of them became a Croatian-Dalmatian Ban. In 1430 they took the surname Frankopan (Frangipane), claiming to have Roman origins. That year they adopted a coat of arms showing two lions breaking a piece of bread (Latin: frangere pane, break bread). From 1449, the descendants of Nikola V founded eight branches of his family, and together with Zrinski Counts were the ruling feudal family in the whole of Croatia right up to 1671. The Frankopans produced seven Croatian Bans, and many of them were patrons of Croatian artists.
Under the Venetians (1480–1797)
Krk was the last Adriatic island to become part of the Venetian Empire. Due to its location, closest to the Uskoks of Senj, it served as a lookout point and the first line of defence against the Uskoks. From that time the ruler was a Venetian noble, but the Small and the Large Councils both had a certain autonomy. The doge controlled the clergy but public documents were written in Glagolitic which was adopted here more than anywhere else. At the beginning of the 16th century the inhabitants of inland Croatia began to settle on Krk in their flight from the Turks, but Krk suffered a decline like all other Venetian property. In 1527 the town had 10,461 inhabitants and in 1527 it had 8,000.
Under the Austrians
This began with the fall of Venice in 1797 and was briefly (1806–1813) interrupted by Napoleon's Illyrian Provinces. In 1822 the Austrians separated the island from Dalmatia and linked it to Istria, so that Krk, Cres and Lošinj came under direct rule from Vienna. This link contributed to the Croatian National Revival and together with Kastav, the town of Krk played a leading role in the spread of Croatian education and culture.
The Italian Occupation (1918–1920) was brief, and Krk was handed over to Croatia, then in Yugoslavia, by the Treaty of Rapallo, Italy took Krk again in the Second World War (1941–1943), and German occupation followed from 1943–1945. The post-war development of Krk was led by tourism. The building of an airport and then a bridge over to the mainland ensures the future of the development of tourism on this island. In Omišalj there has also been industrial development.