Heat oil in a large frying pan on medium. Panfry eggplant for 5 minutes, until browned and tender. Set aside.
Add capsicum and panfry until coloured and soft. Return eggplant to pan with onion and tomatoes, and simmer for 15 minutes. Stir in capers, olives, sugar and vinegar. Season to taste. Simmer gently for another 20 minutes. Cool and serve at room temperature with grilled meats or crusty bread.