Combine the flour, starter, and salt in a bowl and mix with water until a soft dough forms.
Knead the dough on a lightly oiled surface for 15 minutes.
Place the dough in an oiled bowl and let it rise at 22-24°C for six hours.
Knead the olives and oregano into the dough on a surface dusted with flour and semolina.
Divide the dough, shape into rectangles on baking sheets, and cut diagonal holes into them.
Stretch the dough to open the holes and let it rise for four hours.
Preheat the oven to 220°C and place a roasting tin filled with water on the bottom shelf.
Bake the loaves for 20 minutes until golden-brown and cool on a wire rack.