The BL 9.2-inch Mk IX and Mk X guns were British breech loading 9.2-inch (234 mm) guns of 46.7 calibre, in service from 1899 to the 1950s as naval and coast defence guns. They had possibly the longest, most varied and successful service history of any British heavy ordnance.

Georgios Averof is a modified Pisa-class armored cruiser built in Italy for the Royal Hellenic Navy in the first decade of the 20th century. The ship served as the Greek flagship during most of the first half of the century. Although popularly known as a battleship (θωρηκτό) in Greek, she is in fact an armored cruiser, the only ship of this type still in existence.