In 1312, Goa came under the governance of the Delhi Sultanate during the Khilji dynasty. It was during this time that Portuguese colonial holdings went into effect in the area. While Portuguese colonialists settled in Goa there was an unsurprising exchange of cultural trade offs. The Portuguese brought with them Portuguese cuisine, among it a traditional, savoury dish called 'Carne de Vinha d'Alhos' which is essentially a dish of pork stewed in wine and garlic. The recipe was modified by replacing the wine with vinegar and adding other popular Indian ingredients such as chilies, ginger, and other spices.
'Vinha d'Alhos' eventually became accepted as 'Vindaloo' and a new style of curry was born. While originally a pork dish, a meat not quite as popular in that general area of the world, other meats like goat, lamb, and chicken began application to the basic Vindaloo recipe instead.
The original concept of Carne de Vinha d'Alhos does not call for potatoes in the recipe. Though it's not uncommon to find potatoes in Indian Vindaloo. Could there be a reason for that too? Of course! "Aloo" is the Hindi word for "potato" and it is commonly believed that potatoes ended up in the mix over a false assumption produced during lingual miscommunication over the years. So "aloo" was literally added to "vindaloo".
Vindaloo has a reputation for being one of the spiciest curries available in the Western World. Most of that comes from the mix of chilies and the vinegar which replaced the traditional application of wine. Though vindaloo may be the hottest curry on a western Indian menu, it's not necessarily the hottest Indian curry out there.
Personally, I love a nice chicken or goat vindaloo. I will profess that I've never been to India (a fact I hope will change in the future), but I do appreciate the Indian addition of potatoes. Curried potatoes are one of my favourite things to eat!
So next time you order a vindaloo at an Indian restaurant, offer a small "Obrigado" to Portugal. For whom without, there would be no vindaloo.