Final answer:
The statement is false; not all tribes in the Iroquois Confederacy remained neutral during the Revolutionary War, as they were divided, with some siding with the British and others with the American revolutionaries.
Step-by-step explanation:
The statement that all of the tribes in the Iroquois Confederacy maintained neutrality during the Revolutionary War is false. The Iroquois Confederacy, also known as the Six Nations, was initially neutral but eventually became divided over which side to support. This division was largely influenced by the diplomacy of British officials who were able to convince some Iroquois nations to ally with them. Notably, the Mohawk leader Joseph Brant led many Iroquois to fight alongside British forces against the American revolutionaries. This split in the Iroquois Confederacy led to the tribes taking sides, which subsequently resulted in internal conflicts and contributed to the post-war fracturing of the Confederacy.