How did early church writers (Origen, Eusebius, Jerome) argue that Jesus’ brothers were not Mary’s biological children?

1. Origen and the Epiphanian strand: step‑brothers from Joseph’s prior marriage

Origen, followed later by Eusebius and defenders of the Epiphanian view, argued that the “brothers” and “sisters” named in the Gospels were older children of Joseph by a previous marriage, not children of Mary, a position that preserves Mary’s virginity while explaining why the siblings seem older in Gospel anecdotes; this Epiphanian/Origenic line is summarized in modern treatments and linked to Eastern Orthodox tradition ^{[1] [4] [5]}.

2. Eusebius’ use of local tradition and Hegesippus’ memory

Eusebius quoted earlier Palestinian traditions (via Hegesippus and other local sources) to read James and the other relatives as relatives “after the flesh” whose precise relationship could be more complex than immediate maternity, sometimes identifying kin through Joseph’s family or Clopas/Alphaeus links; Eusebius therefore favored non‑maternal explanations rooted in regional oral memory rather than treating Gospel sibling‑lists as proof of Mary’s later childbirths ^{[6] [7] [3]}.

3. Jerome’s polemic: cousins and the linguistic argument for adelphoi

Jerome famously entered a polemical exchange with Helvidius and insisted that adelphoi (brothers) could denote cousins or kin in Semitic and Greek usage, identifying the named brothers as children of “Mary of Clopas,” a different Mary who was presented as Mary of Nazareth’s sister; Jerome’s argument bolstered the doctrine of Mary’s perpetual virginity and became influential in Western Christianity ^{[8] [2] [4]}.

4. Scriptural and pragmatic arguments used by all three

All three fathers appealed to scriptural contexts where the term “brother” could be non‑literal (Paul’s use in 1 Corinthians and broader kinship language), to Gospel scenes (e.g., absence of the brothers at the crucifixion and burial; brothers advising Jesus in John 7) read as suggesting different ages or relationships, and to the silence or ambiguity of Luke’s genealogy; these interpretive moves favored non‑biological readings rather than asserting direct documentary proof ^{[1] [8] [9]}.

5. Motives, theological stakes, and implicit agendas

Their positions were not neutral exegetical footnotes: Jerome’s fierce defense served the ascetic ideal and the emerging prestige of Marian perpetual virginity in the West, while Origenian/Eusebian readings supported Eastern emphases and local traditions about Joseph’s age and role—each reading carried theological and ecclesiastical implications beyond family history ^{[10] [4] [7]}. Modern scholars note these agendas shaped which interpretive cues were favored and later became confessional norms ^{[3] [11]}.

6. Counterarguments and the limits of the early evidence

Critics then and now (e.g., Helvidius and many modern exegetes) argued the plain sense of Mark and Matthew lists implies Mary bore other children; historians point out there is no single decisive contemporary record proving Joseph’s prior marriage or proving that adelphoi must mean cousins, so the early church positions rest on plausible but not conclusive linguistic and traditional inferences ^{[8] [3] [4]}. Scholarship remains divided: some modern scholars prefer the Helvidian (biological siblings) reading, others defend Epiphanian or Hieronymian reconstructions depending on theological and methodological priors ^{[3] [6]}.

7. Bottom line for historical judgment

Origen, Eusebius and Jerome offered coherent, rival non‑biological explanations—step‑brothers from Joseph’s earlier marriage (Origen/Eusebius) or cousins/kin via Mary of Clopas (Jerome)—each backed by appeals to usage, local tradition, or doctrinal concerns; these arguments explain why many ancient churches rejected the plain‑sense reading, but they do not constitute unanimous historical proof and must be read as interpretive traditions shaped by theological aims as much as by exegesis ^{[1] [2] [7]}.