In a medium frying pan, melt oil and butter over medium heat. Reduce the heat, add the onions and sauté until the onions are translucent, about eight minutes. Add the anchovies and garlic and cook for another two minutes. Add the wine and increase heat to a medium-high and simmer until the wine reduces by half. Stir in tomatoes, reduce heat, and simmer for another five minutes. Add artichokes and salt and pepper to taste. Stir and keep warm.