Dénia (Denia) is a historical coastal city in the province of Alicante, Spain, on the Costa Blanca halfway between Alicante and Valencia, and the capital and judicial seat of the comarca of Marina Alta. Denia's historical heritage has been influenced by Iberian, Greek, Roman, Islamic, Napoleonic and Christian civilizations. , it had a population of 43,819, although this is more than doubled by tourism during the summer months.
There is evidence of human habitation in the area since prehistoric times and there are significant Iberian ruins on the hillsides nearby. In the 4th century BC it was a Greek colony of Marseille or Empúries, perhaps the one mentioned by Strabo as Hēmeroskopeion (Ημεροσκοπείον) (meaning "watchtower"). It was an ally of Rome during the Punic Wars, and later was absorbed into the Roman Empire under the name of Dianium (after their goddess Diana). In the 1st century BC Quintus Sertorius established a Roman naval base here.
In 636-696 AD, during the Visigothic Kingdom of Iberia, it was the seat of a bishop from Toledo. After the Muslim conquest of Iberia and the dissolution of the Caliphate of Córdoba, Dénia (known as Dāniyya or دانية in Arabic) became the capital of a taifa kingdom that reigned over part of the Valencian coast and Ibiza. The Slavic Muslim slaves, saqālibah, led by Mujahid ibn Yusuf ibn Ali their leader, who could take profit from the progressive crumbling of the Caliphate's superstructure to gain control over the province of Dénia. The Saqaliba managed to free themselves and run the Taifa of Dénia which extended its reach as far as the islands of Majorca and its capital Madinah Mayurqah. The Saqaliba Taifa lost its independence in 1076, when it was captured by Ahmad al-Muqtadir, lord of Zaragoza, under which it remained until the Almoravid invasion in 1091. The Muslim Arabs originally built the castle fortress, and the French, who occupied the city for four years during the Peninsular War, re-built it in the early 19th century.
The town was reconquered by the Christians in 1244.