The work presented here aims to share the methods and possibilities for studying manuscript sources that are preserved in a fragmentary state by using a concrete example: an early medieval charter of Galician origin which has survived to the present day in a very deteriorated condition. Despite the difficulties its analysis entails, one cannot dismiss this type of evidence because one never knows what information fragmentary documents might be able to offer us in relation to both their author and documentary content. Thus, in the following pages, it is shown how we can establish the charter's approximate chronology, its origin and message by examining its script and diplomatic structure, and by studying the text that still survives in the fragment.