Thanks so much for the comment!
For War of the Pips, there are a ton of influences that contributed to the lore of the world. Its main focus was to capture the wonder I experienced when I was a kid playing games and reading fantasy stories.
World of Warcraft and Zelda are two main contributors. You can see this in certain locations and their names. Kokorin Forest is inspired by Zelda's Kokiri forest. There, you can find the great deku tree that is wise beyond years. This inspired me to create the Ancient Tree. But, what really sealed the deal for me is how universally resonant this idea of wise/knowledgable trees is. We see it Lord of the Rings (Ents), Norse Myth (Yggdrasil), etc.
Lord of the Rings is a cornerstone to my upbringing, and you'll find loads of references there from the Eye, the One Ring, etc.
I also did some research on the French Cards themselves, which resulted in One-Eyed Jack, The Flower Queen, and the Black Lady.
Regarding the European setting, it is indeed the case, though I can't say I consciously leaned into the War of the Roses. I was brought up in British schools and was taught English history, so there definitely is influence there. But, below are what I aimed for to the best of my memory.
Spades - My partner is Slovenian and inspired me to craft the Spades with a Balkan/Slavic flavour. In the Heroes of Spades insert, there is a story of someone who is killed while sitting on a latrine. This actually happened in Predjama Castle, in Slovenia. The King of Spades is also modelled after Vlad Tepes, or dracula.
Diamonds - Inspired by the romance countries, but mainly by the merchant city-states of Italy. We have ships that are a nod to the Venetians and the guild explorers who seek out ancient works (Lorenzo de Medici sent out people to bring back ancient Roman sculptures for artists to learn from).
One fun story is the quest for the Vintners of Vis, which is called Judgement of Vis. Long story, short, it was a wine competition held in France where everyone thought French wines would win. But, being a blind taste test, it turned out that a Californian wine won, which shook the wine world to the core. It was a small story I heard during my hospitality days and thought I'd make a reference here.
And Vis? Vis is an island off the coast of Croatia. It's the island that inspired one of the locations in Porco Rosso, one of my favourite animations.
Clubs - From Tolkien's love of the English countryside, to Robin Hood, the clubs were mostly inspired by English stories.
Hearts - The hearts are inspired by Merlin and European Wiccan traditions. Cardinal witches (think wizard of Oz - witch of the east, west, etc.) is common in Wiccan traditions as the cardinal directions are points of power, often tied to elemental powers. Under Names and Aliases, you will find "witch" names like Befania, a nod to the Italian Befana.
I hope this is a good start to help you begin exploring! :)
