"The Magic Ring, Vol. 3 (of 3)" by La Motte-Fouqué is a novel published in 1812. This chivalric romance follows German knight Otto as he searches for a magical ring to return to its rightful owner. His quest spirals into dangerous intrigues and leads him to the Northern Crusades, where he battles pagans in Finland's dark forests. Blending Gothic elements with medieval adventure, this commercially successful work became Fouqué's most popular historical novel, weaving together European myth-traditions with themes of Christianity and continental unity.
Wikipedia page about this book: en.wikipedia.org/wiki/The_Magic_Ring