This cannonball was fired off the HMS Eclipse, a British warship sent to the coast around Porou pa in 1863. The battle of Katikara was the first conflict of the Second Taranaki Wars, after Governor George Grey made moves to return the unlawfully purchased Waitara block to Te Atiawa, while simultaneously occupying the Tataraimaka block. Grey claimed Ngati Ruanui had unlawful seized this land during the First Taranaki War, and thus in April 1863 the 57th Regiment marched on to the block and established a redoubt followed by Fort St George on Bayly's Farm, near the Katikara River. Members of the Taranaki and Ngati Ruanui iwi viewed this as an act of war, and ambushed a group of Pakeha escorting a prisoner to New Plymouth.

Grey took this as an opportunity to reignite war in the region, with military commander Cameron and 870 troops attacking Porou Pa. The HMS Eclipse provided covering fire. 28 Maori were killed and later buried in a mass grave, now commemorated on the site.

The cannonball was collected by the farmer who owned the land, and he stored all the cannonballs he collected in a pyramid on his verandah. Edward Leslie Hughes asked if he could have this one for his won collection. In 2014 it was donated to the Puke Ariki collection by Hughes' daughter.