The heavy cruiser was designed for long range, high speed, and heavy calibre naval guns. The first heavy cruisers were built in 1915, although it only became a widespread classification following the London Naval Treaty in 1930. The heavy cruiser's immediate precursors were the light cruiser designs of the 1910s and 1920s; the US 8-inch 'treaty cruisers' of the 1920s were originally classed as light cruisers until the London Treaty forced their redesignation. Heavy cruisers continued in use until after World War II.