Complex sentence: Making Slavery History in Massachusetts, 1770-1863 (Harvard University: PhD Dissertation, 2007); The reality, however, was that Attucks was also half Wampanoag, so his story also holds special significance for native Americans.
Split into simpler sentences: Making Slavery History in Massachusetts, 1770-1863 (Harvard University: PhD Dissertation, 2007); Attucks, however, was not only "black". He was half Wampanoag, so his story also holds special significance for native Americans.