Complex sentence: For three centuries beginning in 1515, the remote valleys of Switzerland were more or less isolated from world history, and specific breeds of dogs were created by inbreeding--puppies were given to neighbors and family members.
Split into simpler sentences: For three centuries beginning in 1515, the remote valleys of Switzerland were more or less isolated from world history. Specific breeds of dogs were created by inbreeding--puppies were given to neighbors and family members.