After the indiscriminate shooting of club-goers was over early Sunday in Orlando, 49 people were dead. When the official death toll came out, media and experts almost immediately declared it the deadliest mass shooting in U.S. history, surpassing the Virginia Tech shooting in 2007 that left 33 people dead.

But was this actually the deadliest mass shooting in U.S. history? The short answer: yes, but it depends on how a mass shooting is defined. That definition has been the subject of some contention.

In the aftermath of the Orlando shooting, some publications called the Wounded Knee Massacre in 1890 the deadliest shooting in American history. There, as many of 300—mostly unarmed—Lakota Sioux men, women, and children were killed at the hands of the U.S. 7th Cavalry Regiment. It remains one of the darkest chapters of U.S. efforts to suppress Native Americans, though the 20 Medals of Honor that were given to members of regiment for their participation in the skirmish have yet to be rescinded. But was it the deadliest shooting incident?