I've had this Allen & Ginter Card for some time. Bull Head had joined the Federal Cavalry that surrounded and killed Sitting Bull in 1890. Bull Head apparently fired the first shot that hit Sitting Bull in the chest, but the melee continued ultimately Sitting Bull was also shot in the head. He did not survive.
I found it fascinating that this Bull Head card was produced in 1888 by A & G in the N2 set, two years before the action described in the previous paragraph. Note well that Sitting Bull is also depicted in another N2 card.
The condition of the Bull Head card is unusually good for an N2. Graded N2s above the VG level are indeed rare. I would be happy to discuss the set further will all you N2 collectors on the forum. Selling the card at this time is not my intent. It is also not my intent to collect the entire set either.
The Wikipedia "Sitting Bull" entry gives a fairly good summary of his life and death. The story of the last raid is recounted elsewhere, but the fact that Bull Head shot Sitting Bull is consistent in what I have been able to discover. Any further historical information would be nice to see.
Thanks for looking. Sometimes baseball card collectors are led in unexpected directions.