Complex sentence: Howard wrote a masque which was produced at court during the reign of Edward VI, and is one of the few courtiers mentioned by name in the Langham Letter, which describes the Earl of Leicester's entertainment of Queen Elizabeth at Kenilworth Castle in July 1575.
Split into simpler sentences: Howard wrote a masque which was produced at court during the reign of Edward VI. He is one of the few courtiers mentioned by name in the Langham Letter, which describes the Earl of Leicester's entertainment of Queen Elizabeth at Kenilworth Castle in July 1575.