This article identifies three distinct areas of contact between the Norse and the Gaelic worlds in the Viking and High Middle Ages. Considerations are made of the nature of the material and the purposes for which it was written, the ways in which it has been transmitted or preserved, and the period at which transmission occurred. A particular incident that occurred in 1202 and is recorded in various sagas is examined in order to illustrate the different kinds of evidence that can be used when assessing aspects of the contacts. The purpose is to identify the ways in which different sources can complement each other. This evaluation provides a baseline when considering other events, and helps determine whether there are patterns of source transmission between the two cultural and linguistic areas.