This “Holy Trinity” is the mirepoix of Louisiana Cajun and Creole cooking. So how did we get here?
The French settlers of the region came with their mirepoix of carrot, onion and celery. Chances are, while both the carrot and bell pepper were capable of being grown in the region, the bell pepper was just more readily available and made the sub into the trinity. Also take into consideration that the Spanish settlers were also in Louisiana. Spanish Sofrito (another version of mirepoix) is onions, garlic, bell peppers, and tomatoes. It’s not a stretch to see how the holy trinity came to be.
So Cajun and Creole, what’s the difference? Cajun and Creole are both native to Louisiana, but Cajun actually is derived from the word Acadian, which was the name of the French Canadian settlers in the region. Speaking generally (which I dislike doing), Acadian settlers were more rural. Creole, on the other hand, is a loosely defined ethnic group including native Americans, and immigrants with roots in Africa, the Caribbean, France, and Spain. As one would imagine, you can have a Creole dish, or a Cajun dish, and they can be very similar but would have some differences between the two. Again, speaking generally (booo), the Creole population settled in the city. The cuisine pulls from slightly more sources than their Cajun neighbors.