sentences:  This period was used to reduce government strongpoints in the Highlands, including Blair Castle and Fort Augustus; after its surrender on 1 March, they moved onto Fort William.Advance elements of the Jacobite force arrived outside the fort on 8 March; operations began on 20 March but made little progress.When the Duke of Cumberland and his army left Aberdeen in early April, the besiegers were recalled to Inverness and the siege abandoned.