sentences:  As a result, until the 1870s when the last imperial troops were withdrawn, British regular troops constantly garrisoned the colonies.During their postings to Australia, most of the regiments rotated duties in the various colonies, and often had detachments located in geographically diverse locations at the same time.Accompanying the First Fleet to Port Jackson were three companies of marines totalling 212 men under the command of Major Robert Ross, to guard the fledgling colony of Sydney and that of Norfolk Island, which had been established on 6 March 1788 to provide a food base and investigate supply of masts and flax for canvas for the Royal Navy.