Complex sentence: The 33rd had been renamed the 33rd (The Duke of Wellington's) Regiment on 18 June 1853, by Queen Victoria in honour of the iconic 1st Duke of Wellington, who had died on 14 September the previous year.
Split into simpler sentences: The 33rd had been renamed the 33rd (The Duke of Wellington's) Regiment. The title was granted on 18 June 1853, by Her Majesty Queen Victoria in honour of the iconic 1st Duke of Wellington, who had died on 14 September the previous year.