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
Roman Catholic Diocese of Mariana in Corsica greatly compromised. In 1453 Pope Nicholas V entered into a verbal agreement with the Republic of Genoa, which specified that, although the Pope maintained the exclusive right to appoint bishops on the Island of Corsica, he would appoint only Genoese subjects who were acceptable to the Government. The Genoese government turned the island over to the administration of the Genoese Banco di S. Giorgio, under new statutes for Corsica were issued, the "Capitula Corsorum", which specified that bishops on the island had to be natives of the island. In 1464, however, the Republic of Genoa came under the domination of