Globular jars like this one are today mostly interpreted as grenades. Although still debatable, such objects are believed to have been filled with the so-called ‘Greek fire’, an incendiary substance capable of generating a fire not extinguishable by water, and therefore a useful weapon in naval battles. It constituted an important weapon for the Byzantine Empire but its original formula, kept secret for many centuries, was irredeemably lost following the collapse of the empire. Acquired by the Prince of Wales in 1862