Complex sentence: Jim learned that the Tlingit formline that was considered the traditional method was only a relatively recent development among the Northwest Indian, it was his opinion that enforcing the practices of 1850's or 1950's as the rule for all time amounted to artistic tyranny.
Split into simpler sentences: Jim learned that the Tlingit formline that was considered the traditional method was only a relatively recent development among the Northwest Indian. It was his opinion that enforcing the practices of 1850's or 1950's as the rule for all time amounted to artistic tyranny.