Carthage resident Patrick Murphy filed a plan for a city on the opposite side of the valley and named it Murphysburg. As the nearest sheriff was in Carthage, frontier lawlessness abounded in Joplin. The historic period was referred to as the "Reign of Terror". The cities eventually merged into Union City, but when the merger was found illegal, the cities split. Murphy suggested that a combined city be named Joplin. The cities merged again on March 23, 1873, this time permanently, as the City of Joplin.