Heat the olive oil over medium heat in a large sauce pot. Add the onion and cook until translucent. Add the garlic and cook for 1-2 minutes or until fragrant. Stir in the tomatoes, basil, oregano, salt, sugar, and pepper, and heat until bubbling. Reduce the heat to low and simmer, uncovered, for 1 to 2 hours, until the tomatoes have boiled down to a fairly thick (not watery) mixture. Remove from heat. Strain through Foley food mill, discarding peels and seeds. Taste the sauce and adjust seasoning as necessary. Reheat if necessary; serve over pasta. Serves 6.