In British history, how many years before the Battle of Trafalgar did the Gunpowder Plot take place?

The Gunpowder Plot took place 200 years before the Battle of Trafalgar.

The Gunpowder Plot of 1605, in earlier centuries often called the Gunpowder Treason Plot or the Jesuit Treason, was a failed assassination attempt against King James I by a group of provincial English Catholics led by Robert Catesby who sought to restore the Catholic monarchy from the Church of England after decades of intolerance against Catholics.

The Battle of Trafalgar (21 October 1805) was a naval engagement between the British Royal Navy and the combined fleets of the French and Spanish Navies during the War of the Third Coalition (August–December 1805) of the Napoleonic Wars (1803–1815).