L’Abbé Pègues was a French priest who’d stayed in Santorini and researched the geology and history of the island. In 1837, he wrote his book “Histoire et phénomènes du volcan et des iles volcaniques, suivis d’un coup d’oeil sur l’état moral et religieux de la Grèce moderne” (History and phenomena of the volcano and volcanic islands, followed by a look at the moral and religious condition of modern Greece).
The book was published in Paris in 1842 and became the standard reference work for Theodore Bent, Ferdinand Fouqué, E. M. Leycester and other travellers to the island.
The book is available in the original French to read on-line or as a free eBook download from Google Books.