Thorney Island was the eyot (or small island) on the Thames, upstream of mediaeval London, where Westminster Abbey and the Palace of Westminster (commonly known today as the Houses of Parliament) were built. It was formed by rivulets of the River Tyburn, which entered the Thames nearby. In Roman times (and presumably before), Thorney Island may have been part of a natural ford where what was later called Watling Street crossed the Thames, of particular importance before the construction of London Bridge. Its name came from Anglo-Saxon Þorn-īeg = "Thorn Island".