Robert Mallet was born June 3, 1810, in Dublin, Ireland. His father John Mallet, of Devonshire, owned a plumbing business and copper and brass foundry in Dublin, from which he made a large fortune. He emigrated to Dublin at the invitation of his uncle Robert and married Robert’s daughter, Thomasina Mallet. Only three families can trace their descent in the male line from the Norman conquerors, i.e. those who fought at Hastings in 1066. One of these is Malet (or Mallet).
Robert Mallet was at first a weakling child. As he grew, however, he developed a strong constitution and considerable powers of endurance.