Later, in 1928, the diamond mining company De Beers imported Bullmastiffs to South Africa to guard the mines. This breed was also crossbred with Boerboels in the region. The Boerboel was first introduced to purebred enthusiasts throughout the world, including the United States, by the American anthropologist Dr. Carl Semencic, first in an article in Dog World Magazine and later in his book entitled Gladiator Dogs which was first published by T.F.H. Publications in 1998 and later republished by another publisher in 2013. Semencic credits his early familiarity with the breed to his own travels to South Africa, but especially to his frequent correspondence with the head of the first South African Boerboel club, one Mr. Kobus Rust. Later, the Boerboel Breeders Association was established in 1983 in the Senekal district of the Free State with the sole objective of ennobling and promoting the Boerboel as a unique South African dog breed.