With reinforcements and guidance from the Dominicans, the Cuban rebels defeated Spanish detachments, cut railway lines, and gained dominance over vast sections of the eastern portion of the island. The Spanish government used the Voluntary Corps to commit harsh and bloody acts against the Cuban rebels, and the Spanish atrocities fuelled the growth of insurgent forces in eastern Cuba; however, they failed to export the revolution to the west. On 11 May 1873, Ignacio Agramonte was killed by a stray bullet; Céspedes was surprised and killed on 27 February 1874. In 1875, Máximo Gómez began an invasion of Las Villas west of a fortified military line, or "trocha", bisecting the island. The "trocha" was built between 1869 and 1872; the Spanish erected it to prevent Gómez to move westward from Oriente province. It was the largest fortification built by the Spanish in the Americas.