Complex sentence: Robert Tressell (17 April 1870--3 February 1911) was the pen name of Robert Croker, latterly Robert Noonan, an Irish writer best known for his novel "The Ragged Trousered Philanthropists".
Split into simpler sentences: Robert Tressell (17 April 1870--3 February 1911) was the pen name of Irish writer Robert Croker, who later changed his name to Robert Noonan. He is best known for his novel "The Ragged Trousered Philanthropists".