The Apollo class were second-class protected cruisers designed by Sir William White and built for the Royal Navy in the late 19th century. Twenty-one ships of this class were built, making it the largest single class of steel cruisers ever built for the Royal Navy to the same design.

The Naval Defence Act 1889 was an act of the Parliament of the United Kingdom. It received royal assent on 31 May 1889 and formally adopted the "two-power standard" and increased the United Kingdom's naval strength. The standard called for the Royal Navy to maintain a number of battleships at least equal to the combined strength of the next two largest navies in the world, which then were France and Russia. An extra £20 million over the following four years were provided for ten new battleships, thirty-eight new cruisers, eighteen new torpedo boats and four new fast gunboats. The two-power standard was maintained until disarmament began during the interwar period.