Duke Ernest I of Saxe-Gotha-Altenburg (1601-1675) was a German nobleman and a member of the House of Wettin. He ruled the duchy from 1640 until his death, overseeing a period of reconstruction and development following the Thirty Years' War. His leadership helped stabilize the region and promote economic growth. Ernest I is known for his patronage of the arts and education, founding the {University of Jena} and supporting various cultural initiatives. He also played a significant role in the {Lutheran Reformation}, promoting Protestant values in his territory. His legacy includes a focus on governance and cultural advancement.