Brian McPhelim and some of his relatives acted as intelligence agents to Piers, playing a role in undermining Shane at the Battle of Farsetmore in 1567. Piers as the Seneschal of Clandeboye, was keen to encourage provincial Gaelic clans loyal to the Crown in Ulster as a balance against the influx of Scots, whose presence was unwelcome to the English: a policy which seemingly boded well for Clandeboye. Seeing himself as in a secure position, Brian McPhelim decided to flex his power and waged a private war against the Tyrone successor of Shane, Turlough Lynagh O'Neill. A year after the death of his father, Turlough had declared loyalty to Elizabeth I and so Brian McPhelim's adventurism did not impress the authorities. Elizabeth I made a grant of the entire territory of Clandeboye in 1571 as part of the so-called Enterprise of Ulster: Sir Thomas Smith, her principal Secretary of State was granted what would become north Down and the Ards, while the Earl of Essex was also to be a major beneficiary with a grant of all of County Antrim except for the Route and the Glens (the land had previously been claimed as part of the "Earldom of Ulster" during medieval times, this being the basis of the Crown's grant). The plan was to colonise the land with English Protestants in a foreshadowing of the Ulster Plantation. Sir Brian McPhelim upon finding this out in a booklet published by Smith felt betrayed by the Queen's "duplicity", having felt he was safe in his position due to his allegiance to the Crown and past service to it. Instead of allow his lands to be colonised, Sir Brian McPhelim elected upon a scorched earth policy, burning down any buildings in his territory which could be used as a prospective garrison or could be used for colonisation. Smith had sent his illegitimate son, also named Thomas, along with the 800 English colonists who had set off from Liverpool to Ards: in October 1573, Thomas Smith Jnr was shot dead by an Irishman he had employed as a labourer. A couple of years later Smith Snr had abandoned the project completely. Essex, who had only recently been made an Earl, encouraged by Lord Burghley, was more directly involved on the ground and had most of his fortune at stake. Haunted by an outbreak of plague at Carrickfergus in 1573–74, which decimated Essex's forces,