Apollonia (Greek Απολλωνία) was an ancient city in Hellenistic and Roman Judea, in the Byzantine period renamed to Sozusa (Σώζουσα, or Sozusa in Palaestina to differentiate it from Sozusa in Libya). It was situated on a cliff above the Mediterranean Sea, about 34 kilometres (21 mi) south of Caesarea.
It fell to the Muslim conquest in 640 and was fortified against Byzantine attacks and became known as Arsuf (Arabic: أرْسُوف ʾArsūf, Latinized Arsur). In 1101 it was conquered by the Crusader Kingdom of Jerusalem, and was a strategically important stronghold in the Third Crusade, during which the Battle of Arsuf (1191) was fought nearby. The fortified city and the castle fell to the Mamluks in 1265, when both were completely destroyed.
The site of Arsuf (Tel Arshaf; תֵּל אַרְשָׁף, also Apollonia–Arsuf אַפּוֹלוֹנְיָה-אַרְסוּף) is now in Herzliya municipality, Israel (just north of Tel Aviv). The site was intensively excavated from 1994. In 2002 Apollonia National Park was opened to the public.