Captain is the name most often given in English-speaking navies to the rank corresponding to command of the largest ships. The rank is equal to the army rank of colonel and air force rank of group captain.
Royal Navy captain's rank insignia during Divisions conducted at HMNB Clyde, 2013
Captain from US Navy (at left) and Senior Captain from PLA Navy, 2015
Front page of the Breve Compendio do que pertence à obrigação de hum Capitão de Mar, & Guerra, or "Brief compendium of what pertains to the obligation of a captain of sea and war" (1676)
Portrait miniature of the Portuguese captain of sea and war André de Sousa Ferreira in 1751.
The army rank of captain is a commissioned officer rank historically corresponding to the command of a company of soldiers. The rank is also used by some air forces and marine forces, but usually refers to a more senior officer. Today, a captain is typically either the commander or second-in-command of a company or artillery battery. In the Chinese People's Liberation Army, a captain may also command a company, or be the second-in-command of a battalion.
Captain Törni in the Finnish Army in 1944.