ASTURA, formerly an island, now a peninsula, coast of Latium, Italy, 7m. S.E. of Antium, at the south-eastern extremity 'of the bay of Antium. The name also belongs to the river which flowed into the sea at an anchorage immediately south-east. The mediaeval castle of the Frangipani, in which Conradin vainly sought refuge after the battle of Tagliacozzo in 1268, is built on the foundations of a large villa, with a series of tanks for pisciculture and a harbour for small boats. Along the coast, a mile to the north-west, a line of villas begins, which continues as far as Antium. To the south-east the coast seems to have been as sparsely populated in Roman times as it is now. Astura was the site of a favourite villa of Cicero, whither he retired on the death of his daughter Tullia in 45 B.C. It appears to have been unhealthy even in Roman times; according to Suetonius, both Augustus and Tiberius contracted here the illnesses which proved fatal to them.