James Noel Dillion speculates that "Dermot O’Daly was a chancer, whose rapid advancement was due to the success of the Presidency of Connaught and his ability to turn opportunity to advantage.
For services to the government, on 21 June 1578 Elizabeth I granted him "the entire Manor or Lordship of Lerra with all the towns and castles belonging".
His lands were devastated by Hugh Roe Ó Donnell in January 1597, hundreds of cattle stolen, his tenants and neighbours killed, or afterwards died of starvation.
In the subsequent peace after the end of the war, O Daly adapted to English modes of agriculture, and attracted families with trades/skills to settle in his area.
He promoted the techniques of drainage, quarrying, land cleared of scrub, and hay harvesting to reduce pastoralism in winter.