in Ireland to the Parliamentarians during 1646. However, after fresh negotiations, an alliance was arranged between the Royalists and Confederates in 1648. Some Confederates (most notably the Ulster army) were however opposed to this treaty initiating a brief Irish Catholic civil war in 1648 in which the Ulster Confederate army was supported by the English Parliament. The Scottish Covenanters arrived in Ireland in early 1642 to put down the uprising and thereby protect the lives and property of the Scottish Protestant settlers in Ulster. They held most of eastern Ulster for the duration of the war, but were badly weakened by their defeat by the Confederates at the battle of Benburb in 1646. They fought the Confederates (with the support of the English Parliament) from their arrival in Ulster in 1642 until 1648. After the English Parliament and the Scottish Covenanters' alliance broke down, the Scottish forces in Ulster joined the Confederates and Royalists in an alliance against their former allies in 1649. The Parliamentarian Army gained a major foothold in Ireland for the first time in 1644, when Inchiquin's Cork-based Protestant force fell out with the Royalists over their ceasefire with the Confederates. The Protestant settler forces in the north west of Ireland, known as the Laggan Army (or Laggan Force), also came over to the Parliamentarians after 1644, deeming them to be the most reliably anti-Catholic of the English forces. The city of Dublin fell into Parliamentarian hands in 1646, when the Royalists surrendered it to an English Parliamentarian expeditionary force after the city was threatened by Confederate armies. In 1648 the Parliamentarians briefly gave support to Owen Roe O'Neill's Ulstermen after his fall out with the Confederates: Thus the extreme Catholic and Puritan forces were briefly allied for mutual expediency. The Ulster Catholic army however joined the Confederate-Royalist alliance after the shock of Cromwell's invasion in August 1649. The most potent Parliamentarian force was the New Model Army, which proceeded to conquer Ireland over the next four years and to enforce the Adventurers Act by conquering and selling Irish land to pay off its financial backers. Aftermath The death toll of the conflict was huge. William Petty, a Cromwellian who conducted the first scientific land and demographic survey of Ireland in the 1650s (the Down Survey), concluded that at least 400,000 people and maybe as many as 620,000 had died in Ireland between 1641 and 1653. The