Dissolve yeast in water and mix with flour. Cover with a damp cloth and leave for 1 hour at room temperature. Then go in the fridge for 8 hours or overnight.
main dough
Dissolve yeast in water. Mix and knead with pre-dough, flour and salt. After 5 minutes add olives and knead briefly.
Cover with a damp cloth and leave at room temperature for 45 minutes.
Form the dough into two very large pieces and to oval loaves. Place on a tray covered with baking paper. Put it down again and let it go for another 50 minutes. Preheat oven to 240 degrees.
Dust the bread with some wheat flour and cut diagonally. Pour a cup of water on the bottom of the oven. Bake the breads by 240 degrees for 5 minutes, then go to 180 degrees for 40 minutes.