Short answers, pulled from the story.
Hadrian's Wall was built starting in the year 122 by three Roman legions totaling 15,000 soldiers. The construction took six years to complete the massive stone barrier stretching 73 miles from the River Tyne to the Solway Firth.
The original plan called for a uniform width of 10 Roman feet, but the width was reduced to 8 Roman feet in the eastern half during construction. The wall was originally 10 Roman feet wide and 8 feet high before the reduction in the eastern section.
Almost 10,000 soldiers were stationed along the length of Hadrian's Wall after its completion. These troops came from regiments of auxiliary infantry and cavalry drawn from the provinces rather than the legions who built the structure.
Roman rule in Britain ended by the year 410 when the Roman administration and its legions were gone. Archaeologists have revealed that some parts of the wall remained occupied well into the 5th century before falling into ruin.
John Clayton preserved much of Hadrian's Wall in the 19th century after inheriting Chesters from his father. He began buying land around Steel Rigg near Crag Lough in 1834 to prevent farmers from taking stones and used farm profits to restore sections of the wall.
Hadrian's Wall was declared a World Heritage Site in the year 1987. In 2005 it became part of the transnational Frontiers of the Roman Empire World Heritage Site which also includes sites in Germany.