The ramifications of family myths used in the narrative construction of lives are explored in the light of Alistair Thomson's model of remembering and concept of composure. Just as public legends have been shown to shape the remembering of individual experience, so the myths of a family shape the narrative construction of lives of members of that family. Family myths may be seen as those beliefs that members of a family hold about themselves, their family, and the society in which they live, arising out of their shared history. The investigation focuses on members of one large extended family, the first of whom arrived in New Zealand in 1823 as missionaries to the Maori. Among their many children, several were involved in the Anglican Church and with Maori, while others became wealthy landowners. The life narratives of 52 descendants of these missionaries were recorded using an interactive interviewing technique. It is the first study of its kind in New Zealand, and possibly further afield, throwing light on the multitude of ways members of a particular family can create a usable past out of their common history. Family myths are shown to be fundamental in the construction of memory, and a powerful component in the process of negotiating narratives. The myths arising from the missionary-settler background of this family are multiple. They fall into four main groups: myths associated with land and landownership, those concerned with class and refinement; those concerned with religion and the family's dual tradition as Dissenters and as part of the Anglican hierarchy; and finally those concerned with the Williams family's special relationship with Maori arising from the missionary past. It is argued that family memory and myths are collective memory, the family a mnemonic community. Some of the ways in which family myths are formed and passed on are revealed in the testimonies. It is also shown that the narratives in this cohort were lacking in composure. Within individual narratives there is considerable overlap and interaction between the many different family myths, and also between these and public ideologies such as egalitarianism and biculturalism. Some may interact synergetically, but often they are in conflict. In addition, myths are shown to be subject to gradual metamorphosis according to changing external circumstances. The construction of memory requires constant adjustments to accommodate these conflicting and ever-changing myths. Life narrative remains always partial, provisional and open-ended. We may try to compose our memories in the sense of a process, but we cannot achieve composure, a product. It is suggested that oral historians should reconsider the concept of composure in the analysis of memory and narrative. Particular family myths may also allow narrators to embed themselves deeply into history, extending their links into both past and future well beyond the reach of their own life-spans. The use of myths in this way may also allow narrators to make claims to legitimacy, indigeneity and destiny.