Carl Sylvius Völkner was born in Kassel, Hesse, Germany, probably in 1819; his parents' names are unknown. Trained at the missionary college at Hamburg, Völkner was one of several missionaries sent to New Zealand by the North German Missionary Society. He arrived in New Zealand in August 1849 and worked initially with fellow German Protestant missionary Johann Riemenschneider, in Taranaki. In 1852 he offered his services to the Church Missionary Society. For several years he worked as a lay teacher in lower Waikato. He married Emma Lanfear probably in 1854, and in 1857 was naturalised. He was ordained deacon in 1860 and priest in 1861.
Völkner took charge of the CMS mission station at Opotiki in August 1861. There he worked among Te Whakatohea, who built a church and a school for him. Völkner's significance lies not so much in his life as a missionary, however, but in his death, at the hands of members of his own congregation, on 2 March 1865.
Despite the outbreak of wars in Taranaki and Waikato, Te Whakatohea had remained peaceful. However, by 1864 they were caught up in the debate over whether the East Coast tribes should give support to the Waikato and Tauranga people. Attempts by the East Coast tribes, including Te Whakatohea, to travel to Waikato via Rotorua early in 1864 were resisted by Te Arawa. When they tried to move westward along the coast, they were repulsed by British troops stationed at Maketu and by naval gunfire, sustaining a large number of casualties. Tohi Te Ururangi, a Te Arawa chief, died of wounds received in the battle at Te Kaokaoroa, near Matata. At his tangi, Te Whakatohea chief Te Aporotanga, who had been taken prisoner by Te Arawa, was shot by Tohi's widow, an act which exacerbated the strained relations between the two tribes.
Te Whakatohea were left vulnerable by the combined effects of the battle at Te Kaokaoroa, the loss of Te Aporotanga's leadership, disruption to food cultivation caused by war, and a typhoid and measles epidemic which killed a quarter of the Opotiki population in late 1864. In mid February 1865 a party of Pai Marire emissaries, led by Kereopa Te Rau and Patara Raukatauri, arrived at Opotiki to carry the teachings of the prophet Te Ua Haumene to the East Coast. Their arrival aggravated existing divisions among Te Whakatohea.
Despite hostilities Völkner had remained at Opotiki, making several visits to Auckland in 1864, and again in January 1865. Ignoring warnings from several members of Te Whakatohea, he returned to Opotiki in February with fellow missionary Thomas Grace. Arriving on the Eclipse on 1 March, they learned that Völkner's house had been plundered, and were taken prisoner. The next morning Völkner was led to a willow tree some 200 yards from his church. There, wrote Grace, 'He then knelt down and prayed, and, having shaken hands with his murderers said "I am ready", and, while they continued to shake hands with him, they hoisted him up.' Völkner's body was taken down after an hour and decapitated, and the blood tasted, or smeared on their faces, by the many people present. Kereopa forced out the eyes and swallowed them, describing one eye as Parliament and the other as the Queen and English law. This act of indignity to the head of an enemy conferred mana on Kereopa, and earned him the name Kaiwhatu (the Eye-eater).
In a trial the following day three charges were laid against Völkner: 'His going to Auckland as a spy for the Government'; that 'A cross had been found in his house, and therefore he was a Romanist and a deceiver'; and that he had returned to Opotiki despite instructions to stay away. The evidence that Völkner acted as a spy is well documented in letters he sent to Governor George Grey in January and February 1864. Völkner was aware of the risk he was taking, asking Grey not to publicise the source of the information. A further contributing factor to Völkner's unpopularity at this time was the recall, at Grey's insistence, of the popular Catholic missionary Joseph Marie Garavel, after Völkner had accused Garavel of carrying messages to Opotiki from 'hostile' Waikato Maori. Garavel had also accused Völkner of being a spy. Te Whakatohea saw Völkner as one whom they had adopted into their tribe, but who had betrayed them to the Pakeha governor, and for this reason he was executed.
That it was Pokeno, the son of Te Aporotanga, who 'put the rope round Mr. Völkner's neck', also suggests that Te Whakatohea sought punishment, in the public execution of Völkner, for the murder of Te Aporotanga by Te Arawa. Völkner had commented in his 1864 annual report that Te Whakatohea blamed Grey for not having punished Te Arawa, a pro-government tribe, for this act.
The symbolic action of Kereopa, a member of Ngati Rangiwewehi of Te Arawa, must be separated from the concerns of Te Whakatohea. A number of motives have been attributed to him, including a hatred of missionaries and the Pakeha governor and law, revenge for the killing of women and children by British troops at Rangiaowhia in February 1864, and traditional enmity between Te Arawa and Te Whakatohea. Grace commented that 'the people appeared…so worked up by their new religion as to be ready for any work of the devil'; but he also observed that Patara, the second Pai Marire emissary at Opotiki, was neither present at Völkner's death nor defended it at the trial. The irony is that Pai Marire, meaning good and peaceful, was essentially pacifist and millennial in its teachings. The prophet Te Ua did not give instructions to his emissaries to kill missionaries. The arrival of Patara, Kereopa and their party was a catalyst that led to the tragedy.
In response to Völkner's death, military expeditions were sent to Opotiki in search of his killers, who were regularly described as 'fanatics'. A number of local people were arrested, and some executed. A large area of land, from Matata to east of Opotiki, was confiscated from eastern Bay of Plenty tribes. Lurid accounts, based only partly on evidence, appeared in contemporary newspapers and inflamed Pakeha attitudes towards the 'rebels'. Völkner's body was buried at his church, which was later reconsecrated and dedicated to St Stephen the Martyr.
Whether his death is interpreted as Christian martyrdom or execution as a spy, the issues are more complex. Völkner was described by William Fox as 'a man of remarkable simplicity of character, of the most single-minded and devoted piety, and an extremely conciliatory and kind disposition.' He was known as a 'pro-government' missionary, who tried to maintain the loyalty of his people to the government. It is possible that, as a naturalised subject, he felt a need to demonstrate his own loyalty by providing information to Grey. He may simply have been politically naïve. He 'frequently expressed his confidence in the Opotiki Maoris' on his last voyage to Opotiki in February 1865. Perhaps his simple-minded piety clouded his perceptions. The consequences of Völkner's death, in military action, bloodshed, and land confiscation, created continuing bitterness and division among the tribes of the eastern Bay of Plenty.