The Walbrook is a subterranean river in London. It gives its name to the Walbrook City ward and to a nearby street. It played an important role in the Roman settlement of Londinium. Name The usual interpretation is that the brook's name comes from weala broc meaning "brook of the foreigners" (usually taken to mean the native Britons, who were also referred to as the Welsh). This suggests that there was a British speaking quarter in the city in the Anglo-Saxon period, and this possibility has been linked to the division of the city by the Walbrook, with claims that the Britons lived on Cornhill to the east, while the Saxons lived on Ludgate Hill to the west. Another theory is that it was so named because it ran through or under the London Wall. Geoffrey of Monmouth linked it to the phenomena of the Walbrook Skulls; recounting, or inventing an explanation where the name Gallobroc derived from the name of a vanquished Roman leader called Livius Gallus. The main branch flowing from the parish of Shoreditch was known (above the Wall) as the Deepditch, Flood Ditch or just The Ditch. Division of the City Walbrook divided the city into two hills: Ludgate Hill to the west and Cornhill to the east. It is thought that in the Anglo-Saxon period there may have been two Stallerships in the City, one for the land west of the river, and one for the east. Even beyond the walls, the river separated landholdings, with the Soke of Cripplegate to the west and the Soke of Bishopsgate to the east. By the 11th century the two halves of the City had a distinct economy, character, customs and regulations. The western side was more populous and prosperous, it had the cathedral, the royal palace (which later moved to Westminster) and its large market, Westcheap, was focussed on land-based trade. The east was poorer and more sparsely settled; its smaller market, Eastcheap, was sited near the river to allow it to specialise in seaborne trade. The division of the City into two parts persisted, in a less fundamental way, even to the time of John Stow, writing in 1603. It has been suggested that the probable derivation of the name Walbrook, river of foreigners (i.e. the native Britons), meant that there was a part of the city inhabited by native Britons (also known as Welsh), and