The focus of this thesis is a statistically grounded analysis of early 14th century Norwegian sound patterns using an electronically transcribed corpus of thirty-one royal charters written by four named scribes between 1309 A.D. - 1340 A.D. The written language of these medieval documents is highly variable and it has historically been contested to what extent genuine linguistic and grammatical characteristics can be learned from them. In this study, the written words have been collected into a database where the sound patterns have been analyzed, both in correspondence with written and interpreted phonetic patterns. These patterns have then been compared across scribes to reveal broader regularities as well as deviations. Using this method, genuine sound processes and written tendencies have been distinguished. The results of this investigation are shown to be incongruent with current phonological analyses and a potential pattern of Vowel Harmony not otherwise yet attested among the world's harmonic languages has been identified.