Wikipedia
Seelewig or Das geistliche Waldgedicht oder Freudenspiel genant Seelewig (The Sacred Forest Poem or Play of Rejoicing called Seelewig) is an opera in a prologue, three acts and an epilogue by the German composer Sigmund Theophil Staden.
The libretto by Georg Philipp Harsdörffer (1607—1658), first published 1644 in the fourth part of his Frauenzimmer Gesprächspiele, is based on the schoolplay Ein gar schön geistliches Waldgetichte genant Die glückseelige Seele of 1637, itself translated from L'anima felice favola boschareccia by the Italian Nicolò Negri (1606).
It is the earliest German opera whose music has survived. On the surface, the work seems to be a typical Christian allegory of the soul's journey through this world and the symbolic action takes place in a pastoral setting. Nonetheless, recent inquiries which account for the context of the libretto in Harsdörffer's Frauenzimmer Gesprächspiele have pointed out several problems of a seamless allegoresis. Those readings make it much more likely that Seelewig is bound to its Jesuit pretext in a complex, competitive and even polemic way.
The opera mixes musical numbers and spoken dialogue in a way which foreshadows the Singspiel.