Corsica and killings culminated in the assassination of Prefect Claude Érignac in 1998. In 2013, Corsica hosted the first three stages of the 100th Tour de France, which passed through the island for the first time in the event's 110-year history. Corsica was formed about 250 million years ago with the uplift of a granite backbone on the western side. About 50 million years ago sedimentary rock was pressed against this granite, forming the schists of the eastern side. It is the most mountainous island in the Mediterranean, a "mountain in the sea". It is also the fourth largest island in
Medieval Corsica of unity and central government. Towards the end of the eleventh century, the Papacy laid claim to Corsica, saying it had been donated to the Church by Charlemagne. In fact, all Charlemagne had done was promise that stolen ecclesiastical lands would be returned. Nevertheless, the clergy of Corsica supported the Papacy. In 1077, Pope Gregory VII wrote a letter addressed to the Corsican church, regretting that the Papacy had for so long neglected the island and announcing that he was sending Landulf, bishop of Pisa, as his apostolic legate to the island. In 1092, Pope Urban II raised the bishopric