The town's castle was fortified and garrisoned with troops and some bridges were destroyed to aid its defence.
Although Royalist forces came within 2 miles (3 km) of the town in 1644, the defences were never used and the garrison was stood down the following year.
At the United Kingdom Census 2011, its population was 123,867 including 24,506 students.
Cambridge became an important trading centre during the Roman and Viking ages, and there is archaeological evidence of settlement in the area as early as the Bronze Age.
The fort was bounded on two sides by the lines formed by the present Mount Pleasant, continuing across Huntingdon Road into Clare Street.
The eastern side followed Magrath Avenue, with the southern side running near to Chesterton Lane and Kettle's Yard before turning northwest at Honey Hill.) Anglo-Saxon grave goods have been found in the area.
The first town charter was granted by Henry I between 11.
It gave Cambridge monopoly of waterborne traffic and hithe tolls and recognised the borough court.
The Strawberry Fair music and arts festival and Midsummer Fairs are held on Midsummer Common, and the annual Cambridge Beer Festival takes place on Jesus Green.
During this period, Cambridge benefited from good trade links across the hard-to-travel fenlands.
By the 7th century, the town was less significant and described by Bede as a "little ruined city" containing the burial site of Etheldreda.
Their vigorous trading habits caused the town to grow rapidly.
During this period the centre of the town shifted from Castle Hill on the left bank of the river to the area now known as the Quayside on the right bank.