A mate in 3 from H.F.L. Meyer. Research led me to believe that was the problem that introduced the "Bristol Theme" to the world of Chess Problemists as I claim in the video. However while researching other problems, I've discovered that it appears that I may be the victim of unreliable internet information. It seems that Meyer's problem is not the first instance of the Bristol theme. Most authorities agree that Frank Healy holds the honor, also from 1861. Apparently the issue is that Meyer's problem may not be from 1861 as my sources had indicated- I cannot now determine the actual date of Meyer's problem- and it may be that Meyer was first but for now, given that more authorities claim the honor for Healey, we'll give him the nod.