This thesis takes a fresh, character-based approach to the Íslendingasögur. It is inspired by a narratological study that unites the functional and structural role of characters with their human, individualistic portrayal. My major objective is to demonstrate the important connection between characterisation and structure in the sagas.By drawing attention to characters that I term narrative triggers, I offer a way of reading the sagas that relies both on the narrative conventions of tradition and on the less predictable, personal interactions between the cast of any given saga.In the case of both major and minor figures in the Íslendingasögur a certain type of character is often present to perform necessary motivational functions, allowing the plot to develop.In Part I I emphasise the functional aspect of these characters, before exploring unusual examples that emphasise their individuality in Part II.The motivation of the plot is linked throughout to the figure of the ójafnaðarmaðr. A secondary objective is to provide a clearer understanding of the nature and function of this commonly occurring character type. The ójafnaðarmaðr is frequently alluded to in scholarship,but this thesis provides the first in-depth study of the portrayal of these characters. The quality that informs them (ójafnaðr,‘inequity’, lit. ‘unevenness’) is a threat to one of the core values of saga society and hints at an ‘unbalancing’ of social interactions and of the narrative equilibrium itself. That this unbalance leads to changes in the social structure of the setting is a key factor in driving the plots of the sagas along. For this reason, a detailed examination of the figure of the ójafnaðarmaðr is long overdue: they can be observed to perform a specific narrative function but are always fitted to suit their particular context. Focussing on the structural conventions of character introduction, Part I establishes my methodology and catalogues the examples of characters introduced as ójafnaðarmenn. The scope is limited to those introduced as such because it allows me to establish for the first time the full corpus and conventions of these characters and their introductions. Following developments in our understanding of the oral background to the sagas, my approach to these narratives is built upon the evidence of their shared origins in pre-literate storytelling [...]The intersection between functionality and individuality in character brings certain aspects of the Íslendingasögur to the fore. Part II of this thesis shows that in combination with the structural markers explored in Part I, the sagas employ the collective perspective of the general public, other characters and ‘irrational’ motivators such as fate to contribute to their techniques of characterisation. Because disruptive qualities speak inherently of a difference in the way an individual sees themselves and in the way the public sees them, or we as an audience are meant to see them, figures termed ójafnaðarmaðr are an ideal focal point for the development of this study.