Yu-Gi-Oh Duelist of the Roses takes place in Mid-Century Europe during a war between the Tudors and the Yorkist forces. It is loosly based off of real life Europe.

"Yami Yugi (Yugi Mutou in the English manga and the original Japanese adaptations) assumes the identity of the head of the Tudor dynasty, Henry Tudor, while Seto Kaiba represents the head of the Yorkist forces as Christian Rosenkreuz.

The player assumes the role of the Rose duelist, who has been brought back to Mid-Century England to stop the threat of Zorc Necrophades. However, Christian Rosenkreuz (also known as C. Seto Rosenkreuz) shows up and the player , again , decides which side he or she is going to be a part of. In order to get back home the player needs all 26 of the "Rose Sceptors." 8 Red rose Sceptors are held by the Lancastrians and the 8 white ones by the Yorkists. The player can choose the Red Rose for the Lancastrians, or the player can choose the White Rose for the Yorkists. Each side has different opponents and different endings, but there is an option to restart the game after completion to travel the path you did not choose the first time round."

(From Wikipedia)