"Antrim", named to commemorate the Irish county, was laid down by John Brown &amp; Company at their Clydeside shipyard on 27 August 1902 and launched on 8 October 1903. She was completed on 23 June 1905 and was initially assigned to the 1st Cruiser Squadron of the Channel Fleet together with most of her sister ships. She was sent to Casablanca, Morocco August 1907 following an insurrection that led to the bombardment of Casablanca. She was transferred to the 2nd Cruiser Squadron of the Atlantic Fleet in March 1907 and was then assigned to the reserve Third Fleet at Devonport in April 1909. She was moved to the Mersey during the 1911 Liverpool general transport strike. In December 1912 the ship became the flagship of the 3rd Cruiser Squadron of the Second Fleet.