For much, much, much more on the entire history of Old Sarum and Salisbury, from its prehistoric roots to the 20th century, I highly recommend Edward Rutherfurd's epic, sweeping historical fiction, Sarum: The Novel of England.
Like most of Rutherfurd's other novels, this follows the stories of generations of five invented families woven into the fabric of actual history, rubbing shoulders with historic figures and figuring into historical events.