The defacing of ancient monuments in Egypt started during pharaonic times, with Middle Kingdom pharaohs removing carved stones for reuse in their own (mostly mud brick) monuments. By Roman times the so-called Memnon Colossi had graffiti carved all over them (one of the surviving ones is by a Roman emperor). When Christianity arrived, old school temples were adapted as churches. Islam brought the usual pain and suffering, and led to more recycling of stone. The exterior limestone finish blocks of the Great Pyramid were stripped for construction projects in Cairo, and the pyramid of Djedefre (Khufu's son and successor; predecessor to the better known Khafre), which was probably left unfinished during the Old Kingdom was treated as a quarry of finished stone and just vanished. During European colonial times, the monuments of Egypt were better appreciated by the visitors / conquerors, and major excavations and plundering went on, under the auspices of whatever government was in charge.