William the Conquerer visited Sarisberie (Old Sarum) at least twice. In 1070 he reviewed and paid off his army of soldiers who had invaded England four years earlier. (i)
In 1086, according to the Anglo Saxon Chronicle "There all his counsellors came to him and the people occupying land who were of any account all over England."
It was the ideal ceremonial meeting place. The outer enclosure of the hilltop site could accommodate large numbers. Old Sarum also lay at a junction of six Roman roads, and the castle was second only to Winchester as a centre of royal government. (i)
The collation of the Domesday Book had taken place at Old Sarum and had been completed the previous year. It would therefore be fair to assume that a copy of it would have been presented to William during the ceremony at which all the principal landowners, the prelates, nobles, sheriffs and knights, swore their fealty to him.
Estimates vary as to how many people attended this Great Council or Oath of Salisbury. Historian Marc Morris puts the figure "well into four figures, and just possibly nudging towards five." (ii)
Looking at the peaceful hill-side today it is difficult to imagine such a massive crowd occupying it, if only for a few days.
(i) English Heritage www.english-heritage.org.uk/learn/story-of-england/medieval-part-1/oath-of-sarum/ accessed 22 March 2017
(ii) Marc Morris, The Norman Conquest (First published 2013 Windmill Books) p319