Complex sentence: Despite the vastness of his archives, Boyer uniformly declined to allow critics access to his repository, entrusted to him directly from the families involved in the Earp saga, and many began to criticize his work.
Split into simpler sentences: Despite the vastness of his archives, Boyer uniformly declined to allow critics access to his repository. The documents were entrusted to him directly from the families involved in the Earp saga, and many began to criticize his work.