Nor are we told by any ancient author whether Helena set out on her journey from Trier, Rome, Nicomedia, or some other place; we do not even know whether she traveled by land or by sea. If she traveled by land, in either direction, it is most likely that she passed through Syrian Antioch. Her presence in the area contributed, in any event, to the downfall of Eustathius, the bishop of Antioch.
Several ancient sources report that Eustanthius was driven from his see. Eusebius of Caesarea could have succeeded to the vacant see, but he declined and won Constantine's praise in the process (VC 3.59-62). Jerome dates this event to the year 328 and attributes Eustathius; fate to the stance which he had taken in the Arian controversy:
... XXIII Eustathius, quo in exilium ob fidem truso usque in praesentem diem Arriani ecclesiam obtinuerunt.
Athanasius also gives Eustathius high marks as a defender of orthodoxy and adds that his enemies had brought false charges against him before Constantine; specifically Eustathius was said to have offended Helena, [some Greek]. (Athanasius, Hist. Arian.) Unfortunately Athanasius does not tell us what the nature of Eustathius' alleged [Greek word] was.
Socrates tells us that Eustathius was deposed by a synod of bishops which met in his own city; he then describes the dissension which prevailed within the church. There is no mention of Helena; neither is there in the parallel accounts of Sozomen and Theodoret.
Jerome, as previously mentioned, dates Eustathius' exile to the year 328. Henry Chadwick has argued that the council of which Socrates, Sozomen, and Theodoret speak was held in 326. Further refining Chadwick's arguments, Barnes has proposed 327. Any of these dates would coincide with Helena's pilgrimage to the Holy Land. Whether Eustathius insulted her to her face or made a disparaging remark in her absence we cannot tell.
Hans A. Pohlsander, Helena: Empress and Saint (Chicago: Ares Publishers, Inc., 1995), pp. 85-87.
There was one Eustathius, Bishop of Antioch, a Confessor, and sound in the Faith. This man, because he was very zealous for the truth, and hated the Arian heresy, and would not receive those who adopted its tenets, is falsely accused before the Emperor Constantine, and a charge invented against him, that he had insulted his mother. And immediately he is driven into banishment, and a great number of Presbyters and Deacons with him. And immediately after the banishment of the Bishop, those whom he would not admit into the clerical order on account of their impiety were not only received into the Church by them, but were even appointed the greater part of them to be Bishops, in order that they might have accomplices in their impiety. Among these was Leontius the eunuch, now of Antioch, and his predecessor Stephanus, George of Laodicea, and Theodosius who was of Tripolis, Eudoxius of Germanicia, and Eustathius, now of Sebastia.
Athanasius, Historia Arianorum (online).