This exceptional mask with original patina belongs to the Baulè (or Baoule) population. 
 
The baulé are descendants of refugees who fled Ghana to the Ivory Coast in the 17th century, during the rise of the Ashanti kingdom. 
This origin is recorded in the oral baulé tradition with a legend. 
Legend goes that in the 17th century the Baoulé left present day Ghana and traveled west into present day Côte d'Ivoire under the lead of the Queen Pokou. According to oral tradition, the Baoulé were forced to leave Ghana when the Ashanti rose to power. 
While they were fleeing for their lives they came to the Komoe river which they were unable to cross. With their enemies chasing them they began to throw their most prized possessions into the river.
 It came to the Queen's attention that their most valuable possession was her son. The Queen realized that she had to sacrifice her son to the river and threw him in. 
Upon doing so hippopotami rose from the river and allowed them to cross, saving their lives. After crossing, the Queen was so upset about losing her son that all she could say was "baouli," meaning: the child is dead. From that point on they were known as the Baoulé