Chromatius served as bishop of Aquileia, a large trade-centered city at the north end of the Adriatic Sea, from 388–407. He interacted with notables like Rufinus, Jerome, Ambrose, and John Chrysostom, but our knowledge of Chromatius was limited to second-hand statements until the rediscovery of his sermons in the last century. When one examines the sermons in their original context, a disconnect on the issue of heresy emerges. Based on a survey of Christianities in northern Italy, it seems that the variety we might expect is lacking in the sources. An examination of the region reveals that the area during this time was remarkably homogenous in terms of the diversity among its Christian adherents. In Aquileia, Chromatius would have been unchallenged by other churches. In light of that, what did his continued tirades against non-existent “heretical” groups achieve? By examining the whole of each sermon mentioning heretics a pattern emerges surrounding the history of heresy and orthodoxy. The maintenance of institutional memory was not done sentimentally, but to advance the domination Christians had achieved into new arenas, namely, for Chromatius, control over an urban religious space which included Judaism.