James M. McPherson, Ordeal by Fire: The Civil War and Reconstruction, 3rd ed. (New York: McGraw-Hill, 2001), 82-83.
In 1854, a major filibustering enterprise overlapped the official efforts to buy Cuba. The leader of this venture was former Governor John A. Quitman of Mississippi…During the 1850s, American filibusters, mostly from Texas and California, launched dozens of raids into Mexico. Some of them had simple plunder as their goal; others were part of a sporadic border warfare that continued for years after the Mexican war.