According to family information, Marianne Coldham was born in Yorkshire, England, on 12 December 1793, the eldest daughter of Ann Temple and her husband, Wright Coldham. In 1796 her family and that of her future husband, Henry Williams, moved to Nottingham to try their fortunes in the lace making industry. When Marianne married Henry in 1818, she was described as 'tall – about 5 ft. 9 ins. – slender, very fair, with large blue eyes and a dazzling complexion'. The marriage ceremony took place on 20 January 1818 at Nuneham Courtenay, Oxfordshire. Over the next four years, in preparation for missionary work in New Zealand, Marianne trained as a cook, nurse, midwife and teacher. When Henry took his ordination vows in 1822, she stood beside him as he gave an unusual promise: 'she does not accompany me merely as my wife, but as a fellow-helper in the work'.
On 3 August 1823, with Henry and her three young children, Marianne arrived on the Brampton at the Bay of Islands, New Zealand. With Henry fully involved in mission work and constantly journeying, she was often alone there, but, as her husband said, the settlement at Paihia seemed to 'hang together by her being in her place'. She had an exceptional capacity to deal with challenges. Indefatigable and spirited, she was endlessly active in many roles. Her home – first a raupō hut with no kitchen, then two mud cottages, and finally a wooden house with several adjacent buildings, described as 'elastic dependencies' – served as refuge, hospital, hostel, church, school, and official residence, and was later known affectionately as 'Williams' Hotel'. From 1826 Marianne's sister-in-law, Jane Williams, shared in mission responsibilities, the two women rearing and educating their families in a single, supportive community.
From the outset Marianne Williams, corsetted by conviction, sought to 'save' Māori women and girls by giving them Christian values and Western skills. As part of this endeavour she fought constantly to keep them from 'the shipping'. With Jane Williams's help she opened a boarding school for young Māori women. They also opened the first English girls' school, for the daughters and younger sons of the CMS missionaries. A network of schools was built up under Marianne's control, and until she left Paihia she continued to train and supervise their teachers, many of whom were her daughters, nieces or future daughters-in-law. They continued her work at other mission stations.
Marianne Williams was the first substantial witness to record, from a woman's point of view, early domestic interaction among Māori and Pākehā. From the moment she left England she wrote incessantly. Through journals and hundreds of letters she maintained a vital web of information and support for family and fellow workers. She had a magpie eye for detail, a wry humour and a sharp perception of human behaviour. In dramatic situations adrenalin as well as ink helped her facile pen to flow, as demonstrated by her account of the family's removal to Pākaraka on 31 May 1850, within a week of receiving the news of Henry's dismissal by the CMS authorities: 'Then it appeared as tho by magic we had been taken up in our habitation and been transported through the air and set down here'. The solidarity shown at this time within her loving family – now grown to 11 – was sustained throughout Marianne's life with Henry at Pākaraka, and continued after his death there on 16 July 1867. Marianne Williams died on 16 December 1879 and lies with her husband in the Pākaraka churchyard.