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Gabriel Sylliboy (August 18, 1874 – March 4, 1964) was the first Mi'kmaq elected as Grand Chief (1919) who was the first to fight for treaty recognition - specifically, the Treaty of 1752 - in the Supreme Court of Nova Scotia (1929).
Sylliboy was born at Whycocomagh Reserve in Cape Breton. A son of John and Mary (Barrington) Sylliboy. Before 1918, Gabriel was already a renowned Mi'kmaq religious leader at Whycocomagh Reserve and Grand Captain of the Mi'kmaq grand Council.
In 1929, Mi'kmaq Grand Chief Gabriel Sylliboy was arrested for hunting out of season. He used the treaties as his defence but was subsequently convicted. It was not until the treaties were enshrined the Canadian Constitution in 1982 that they began to be recognized by the courts. In 1985, based on the 1752 Treaty, the Supreme Court of Canada affirmed James Simon from Nova Scotia had the right to hunt for food anywhere in Mi'kmaq country. Then came a court decision that recognized the Mi'kmaq right to fish for food. Next, the Marshall ruling said the treaties show the Mi'kmaq can earn a living from hunting and fishing as their ancestors did when they traded with the Europeans. 
While Sylliboy could not speak, read, or write English, he was adamant his grandchildren be formally educated in English while at the same time remain immersed in the Mi'kmaq culture and language.
- namesake of Gabriel Sylliboy Road in Whycocomagh 2, Nova Scotia, Canada.
- William C. Wicken. The Colonization of Mi'kmaw Memory and History, 1794-1928: The King V. Gabriel Sylliboy. University of Toronto Press. 2012.