Same Name Syndrome

I'm working through editing and re-setting the scripts for the first tetralogy of The Kingship Cycle, and last night was devoted to 3 Henry VI. Luckily, this script is in really good shape. I fixed a few typos and reset the character names. King Henry VI is sometimes set as "Henry" and sometimes as "King." King Edward IV - same thing. But there's also Prince Edward, son of Henry VI, who fortunately is usually set as Prince.

Throughout these 8 history plays, the characters have good, strong English names. How are we supposed to keep them straight?

My approximate count (since I'm certain to be missing at least a few) is:

• 7 Henrys
• 6 Edwards (technically Edward III and the Black Prince of Wales are only mentioned)
• 4 Richards
• 4 Edmunds
• 2 Humphreys
• 1 George
• 8 Johns
• 3 Thomases
• By the time I got to William, I gave up.

I finally feel after having performed in 5 of these 8 plays in the past, seen films and theatrical productions, read them multiple times like I can begin to keep many of these names straight with titles. How do I make this easier on an audience member who perhaps has never seen 1 Henry IV? Or an actor who is familiar with Richard III but not 2 Henry VI? Maybe I should invest in a wall poster on the genealogy of England's Royal Houses.