Violence against Native Americans during this event culminated in the Bridge Gulch Massacre. During 
Violence against Native Americans during this event culminated in the Bridge Gulch Massacre. During this event, devices such as the Long Tom were used extensively for the first time. The land where this event began was granted to its owner by Juan Alvarado, the local governor, and was known as New Helvetia. Samuel Brannan started this event by being very indiscreet with a discovery that was made by James W. Marshall. A massive influx of prospectors ruined the lands of John Sutter during this event, causing him to go bankrupt. For 10 points, name this event in which "forty-niners" descended upon a newly acquired American territory in search of a precious metal.