L’objectif de cette thèse est de présenter les stratégies du négoce landernéen de la fin du XVIIe siècle au milieu du XIXe siècle. L’implantation de la Marine Royale à Brest à la fin du XVIIe siècle pour préparer la « Seconde guerre de Cent Ans » la perte du marché anglais pour les crées du Léon, les guerres incessantes entre 1744 et 1815, les crises de toute nature, la perte du marché espagnol et de ses colonies dans les années 1820, voilà autant de défis à relever pour la communauté marchande landernéenne. Elle développe un commerce actif et saisissant toutes les opportunités, s’efforce d’y faire face. Renforcée par des apports allogènes, elle se transforme en groupe dominant, s’installant au sommet de la hiérarchie financière et, en 1721, s’empare du pouvoir local dans une ville qui devient pleinement négociante. Elle peut ainsi orienter l’action publique au service de ses ambitions et, réaliser ainsi un équipement portuaire adapté aux besoins de trafics en expansion. Près de ce poumon économique s’édifient les hôtels particuliers témoignant de la réussite des négociants. Lorsqu’au début des années 1820, la Révolution libérale espagnole et l’émancipation des colonies ferment définitivement ces marchés aux toiles bretonnes, le principal groupe marchand de la ville engage, cas unique en Bretagne, une étonnante reconversion industrielle, afin de se positionner en leader sur les marchés de fournitures militaires. Cette révolution, indispensable pour répondre aux exigences de prix et de qualité du donneur d’ordres, aboutit à la création en 1845 de la Société Linière du Finistère, qui devient la plus importante entreprise privée du Finistère, salariant jusqu’à 4 500 employés. / In this thesis, we aim at presenting the merchants strategies in Landerneau from the end of the XVIIth century to the middle of the XIXth century. The French Navy based in Brest at the end of the XVIIth century – in order to prepare for the « Second Hundred Years’ War » - as well as the loss of the English market by the crées (linen canvas) of Leon, the constant wars betwenn 1744 and 1815, the crisis of all kinds, the loss of the Spanish market and its colonies during the 1820’s, constituted several challenges to address for Landerneau’s merchants’ commmunity. Developping an active trade, this community tried to face every new opportunity. Reinforced by external additions, it became a dominant group, getting the upper place of the financial hierarchy. In 1721, it managed to take over the local government, making the town to fully becoming a trade place. The public policy could then be turned to serve the goals set up by this group, like building new harbour facilities, matching with the needs of an expanding traffic. The beautiful mansions built nearby this economical backbone, are as many testimonies of the merchants’ achievement.When, at the beginning of the 1820’s, the Spanish liberal revolution and the emancipation of the colonies definitly closed those markets to canvas from Brittany, an amazing industrial restructuring was engaged by the main merchant’s group of the town, in order to become leader on the market of military supply. This is a unique case in Brittany. This revolution, essential to respond to the price and quality requiered by the payer, leaded to the creation in 1845 of the Société Linière du Finistère (Linen Society of Finistère), which became the main private compagny of Finistère, employing up to 4500 people.

This thesis assesses climate change during the Hypsithermal Climatic Interval through the analysis of freshwater mussel remains from archaeological sites in Eastern North America. Modern climate data was used as a model to test the mosaic consequences of climate change. Freshwater mussels: can be used as indicators of precipitation by examining changes in overall size through time: larger mussels are found in larger streams, while smaller mussels are found in smaller streams. This study combines morphometric and isotopic data from archaeological freshwater mussels at Modoc Rock Shelter, Watson Brake, Plum Creek, Owens site, and Landerneau mounds to assess past climatic conditions. At Modoc Rock Shelter, oxygen isotopic data corroborate morphometric data and show that climate was fluctuating with a period of stability at the onset of the Hypsithermal. The oxygen isotopic data sets from the Louisiana sites show that the mid-Holocene was much warmer than the late-Holocene.