In 1840, Isaac Graham allegedly began agitating for a Texas-style revolution in California, in March issuing a notice for a planned horse race that was loosely construed into being a plot for revolt. Alvarado notified Vallejo of the situation, and in April the Californian military began arresting American and English immigrants, eventually detaining about 100 in the Presidio of Monterey. At the time, there were fewer than 400 foreigners from all nations in the department. Vallejo returned to Monterey and ordered Castro to take 47 of the prisoners to San Blas by ship, to be deported to their home countries. Under pressure from British and American diplomats, President Anastasio Bustamante released the remaining prisoners and began a court martial against Castro. Also assisting in the release of those caught up in the Graham Affair was American traveler Thomas J. Farnham. In 1841, Graham and 18 of his associates returned to Monterey, with new passports issued by the Mexican Federal Government.