delegates to the Maine Constitutional Convention in October 1819. On February 25, 1820, the General Court passed a follow-up measure officially accepting the fact of Maine's imminent statehood. At the time of Maine's request for statehood, there were an equal number of free and slave states. Pro-slavery members of the United States Congress saw the admission of another free state, Maine, as a threat to the balance between slave and free states. They would only support statehood for Maine if Missouri Territory, where slavery was legal, would be admitted to the Union as a slave state. Maine became the nation's 23rd state on March 15, 1820, following the Missouri Compromise, which allowed Missouri to enter the Union as a slave-holding state and Maine as a free state. However, Massachusetts still held onto the vast offshore islands of Maine after allowing it to secede, because of the high number of people on them who still wished to remain part of Massachusetts. This only lasted until 1824, when the cost of supplying the islands that were now very hard to access directly from Massachusetts outweighed any profit from holding onto those islands. Massachusetts formally ceded the last of its islands near Maine in late 1824. William King was elected as the state's first Governor. William D. Williamson became the first President of the Maine State Senate. When King resigned as governor in 1821, Williamson automatically succeeded him to become Maine's second governor. That same year, however, he ran for and won a seat in the 17th United States Congress. Upon Williamson's resignation, Speaker of the Maine House of Representatives Benjamin Ames became Maine's third governor for approximately a month until Daniel Rose took office. Rose served only from January 2 to January 5, 1822, filling the unexpired term between the administrations of Ames and Albion K. Parris. Parris served as governor until January 3, 1827. The Aroostook War The still-lingering border dispute with British North America came to a head in 1839 when Maine Governor John Fairfield declared virtual war on lumbermen from New Brunswick cutting timber in lands claimed by Maine. Four regiments of the Maine militia were mustered in Bangor and marched to the border, but there was no fighting. The Aroostook War was an undeclared and bloodless conflict that was settled by diplomacy. Secretary of State Daniel Webster secretly funded a propaganda campaign that convinced Maine leaders that a