Combine olive oil and butter in a saucepan and heat. Chop garlic and parsley together and add to the pan. Cook slowly for 5 minutes, then add salt and pepper.
Drain the tomatoes and chop the solids. Add the chopped tomatoes and oregano to the sauce and cook slowly for 30minutes.
Add anchovies and tomato paste, stir well, and remove from the heat.
At the end of cooking, taste for salt and add some if necessary, but remember, the anchovies will make the sauce salty.