sentences:  O'Neill himself was promptly arrested by the United States authorities acting under the orders of President Ulysses S. Grant.After resigning as president of the Fenian Brotherhood, John O'Neill unsuccessfully attempted an unsanctioned raid in 1871, joining the forces of his remaining Fenian supporters with exiled members of the Red River Rebellion.The raiding party crossed the border into Manitoba at Pembina, Dakota Territory and took possession of the Hudson's Bay Company trading post on the Canada side.