Bath city walls the Romans, to surround their town (known then as "Aquae Sulis"), probably in the 3rd century. The Anglo-Saxons by the 10th century had established Bath as a fortified "burh" (borough), utilising the existing town walls, and maintaining Bath as a centre of regional power. Bath, located on the northern edge of the kingdom of Wessex, would have guarded against any attack from neighbouring Mercia, which was held by the Danes for a time. The height of the walls was increased on the orders of King Stephen during The Anarchy. Bath's medieval walls included four gates. The North and South Gates
Albulae Aquae fact." Albulae Aquae Albulae Aquae ("The White Water") is a group of springs located West of Tivoli in Italy. The springs' water is bluish, strongly impregnated with sulphur and carbonate of lime, and rises at a temperature of about . The remains of a Roman thermal establishment exist near the principal spring, the so-called Lago della Regina, which is continually diminishing in size owing to deposits left by the water. Dedicatory inscriptions in honour of the waters have been found at the site. It is mentioned briefly by many ancient authors, among them, Virgil, Vitruvius, Isidore of Seville, and Pliny