In large bowl, dissolve yeast with warm water. Add olive oil, oregano and olives. Gradually add salt and enough flour to form a smooth dough. Cover with a tea towel and let rise in warm place until double in volume.
Punch dough down and divide into two. Shape each piece into a loaf and sprinkle with feta and chopped tomato. Bake at 180 C / Gas 4 for 40 minutes.