Complex sentence: The fate of the manuscript was unknown until it was rediscovered 177 years later by Cristina Dazzi in the summer of 1997 in Italy at the home of the Dazzi family, Casa Cini, in San Marcello.
Split into simpler sentences: The fate of the manuscript was unknown until it was rediscovered 177 years later by Cristina Dazzi in the summer of 1997. She found at in the home of the Dazzi family, Casa Cini, in San Marcello.