Complex sentence: In 1981, Larson had promised to shave his beard if the Bruins won the Stanley Cup; he shaved his beard 30 years later, after the Bruins defeated the Vancouver Canucks the 2011 Stanley Cup Finals.
Split into simpler sentences: In 1981, Larson promised to shave his beard if the Bruins won the Stanley Cup. Larson shaved his beard 30 years later after the Bruins defeated the Vancouver Canucks the 2011 Stanley Cup Finals.