Complex sentence: Sir John Marlay (1590-1673) was an English merchant, military commander and politician of the seventeenth century, who is best remembered for his heroic defence of Newcastle-upon-Tyne during the English Civil War, in behalf of the Royalist cause.
Split into simpler sentences: Sir John Marlay (1590-1673) was an English merchant, military commander and politician of the seventeenth century. He is best remembered for his heroic defence of Newcastle-upon-Tyne during the English Civil War, in behalf of the Royalist cause.