Please answer a question about the following article about Montana:

Under Territorial Governor Thomas Meagher, Montanans held a constitutional convention in 1866 in a failed bid for statehood. A second constitutional convention was held in Helena in 1884 that produced a constitution ratified 3:1 by Montana citizens in November 1884. For political reasons, Congress did not approve Montana statehood until 1889. Congress approved Montana statehood in February 1889 and President Grover Cleveland signed an omnibus bill granting statehood to Montana, North Dakota, South Dakota and Washington once the appropriate state constitutions were crafted. In July 1889, Montanans convened their third constitutional convention and produced a constitution acceptable by the people and the federal government. On November 8, 1889 President Benjamin Harrison proclaimed Montana the forty-first state in the union. The first state governor was Joseph K. Toole. In the 1880s, Helena (the current state capital) had more millionaires per capita than any other United States city.

Why was this constitutional convention held?
bid for statehood