in the west germanic variety that gave rise to old english, "a"-mutation did not affect the second element of the diphthong (for which the earliest old english texts have "eu"): "treulesnis" "faithlessness", "steup-" "step-" (epinal glossary 726, 1070); but in other branches of west germanic eventually became unless followed by , e.g. old saxon "breost" "breast" vs. "treuwa" "fidelity". in most variants of old norse, > > or , without regard to "a"-mutation, e.g. old icelandic "djúpr".