During this time Grass was apparently captured by French forces and imprisoned at Fort Frontenac around 1756, where he gained an appreciation for the Cataraqui area.
[2] In 1777, at the beginning of the American Revolution, Grass returned to New York City because Tryon County became too dangerous for Loyalists.
[2] In 1783, Grass and a group of Loyalist families were sent by Sir Guy Carleton to settle on the north shore of Lake Ontario.
From New York City they headed to Sorel, Quebec in the fall of 1783 and were given permission later that year by Governor Frederick Haldimand to settle at the location preferred by Grass - Cataraqui (later named Kingston).
[5] He became a leader in the new community, creating one of the first permanent English-speaking towns in Canada.