Short answers, pulled from the story.
Harvey of Léon, also recorded as Hervey le Breton, was the first Earl of Wiltshire, created in 1139 after he married Sybilla, an illegitimate daughter of King Stephen. The title lapsed after he lost his English lands during the civil war known as the Anarchy.
The first Earl of Wiltshire, Harvey of Léon, lost his English lands during the Anarchy, and at that time nobody could hold the rank of earl without the territory to support it. The earldom lapsed as a result and was not revived until Patrick of Salisbury received a second creation, probably after July 1143.
The Earl of Wiltshire title has been created seven separate times, beginning in 1139 and ending with the seventh creation in 1550. Most of the earlier creations lapsed within one or two generations, through forfeiture, execution, or a lack of male heirs.
William le Scrope, created Earl of Wiltshire in 1397, was executed amid the events that led to Henry IV deposing King Richard II. James Butler, who received the earldom's third creation, fought on the Lancastrian side at the Battle of Towton and was executed and posthumously attainted afterward.
Thomas Boleyn, the father of Anne Boleyn, received the earldom's sixth creation in 1529 and was a great-nephew of James Butler, the earl of the 1449 creation. He outlived his own son, and when he died in 1539 with no other male heir, the title became vacant again.
The Earl of Wiltshire title is currently held by the Marquess of Winchester and is used as a courtesy title for the marquess's eldest son. William Paulet received the earldom's seventh and final creation in 1550 and was made Marquess of Winchester the following year, and his descendants have held both titles since.