There has been another discussion here about Jesus’ so-called “brothers”, and, apart from a lot of confusion about a Greek word (αδελφος) which does not mean what the English “brother” does (e.g., Plato uses it to describe laws which are similar to one another), there has been some … misunderstanding of what Eusebius of Caesarea says about Jesus’ family.
1.12 James, ‘εις …] των φερομενων του σωτηρος αδελφων (“one …] of the alleged brothers of the the saviour”)
2.1 James, τον του κυριου λεγομενον αδελφον οτι δη και ‘ουτος του Ιωσηφ ωνομαστο παις (“the one called the brother of the lord just as also this one [Jesus] was called the child of Joseph”)
2.1 Joseph, του δε Χριστου πατηρ (“father of Christ”)
2.1 James, τον του κυριου αδελφον (“the brother of the lord” – quoting Gal 1:19)
2.23 James, τον του κυριου …] αδελφον (“the brother of the lord”), once as narrator, once quoting Hegesippus, once quoting Josephus
3.11 γενους κατα σαρκα του κυριου (“the clan - according to the flesh - of the lord”)
3.11 Simeon, ανεψιον, ‘ως γε φασι, γεγονοτα του σωτηρος, τον γαρ ουν Κλωπαν αδελφον του Ιωσηφ (“the cousin, as it is said, related to the saviour, Klopas [being] the brother of Joseph”)
3.19 grandsons of Judas, τουτον δ’ ειναι αδελφον κατα σαρκα του σωτηρος (“the one [claimed] to be the brother - according to the flesh - of the saviour”)
3.20 (very shortly after 3.19) Judas, του κατα σαρκα λεγομενου αυτου αδελφου (“the one - according to the flesh - said [to be] the brother of him [the lord]”)
3.22 James, τον του σωτηρος ‘ημων αδελφον (“the brother of the saviour of us”)
3.32 grandsons ‘ενος των φερομενων αδελφων του σωτηρος (“of one of the alleged brothers of the saviour”)
3.32 απο γενους του κυριου (“from the clan of the lord”)
3.32 Simeon, the son εκ θειου του κυριου …] Κλωπα (“of the uncle of the lord, Klopas”)
4.5 James, ‘ο του κυριου λεγομενος αδελφος (“the so-called brother of the lord”)
4.22 Simeon, ανεψιον του κυριου (“cousin of the lord”)
Eusebius says that Jesus was conceived εκ πνευματος ‘αγιου (“via the Holy Spirit”), and identifies James very early on as being Jesus’ brother in the same sense that Joseph was Jesus’ father (2.1), i.e. not really at all. Eusebius then fairly consistently, even insistently, qualifies such expressions as “brother of the lord” with expressions for report or allegation (rendered above as “alleged” or “so-called”: 1.12, 2.1, 3.19, 3.20, 3.32, 4.5). Only twice does he use just “brother” (2.23, when he also quotes two other people using that short form, and 3.22), and he does similarly use just “father” for Joseph’s relationship to Jesus (2.1). He also qualifies other references to Jesus’ relatives as “according to the flesh” (3.11) or even “reportedly according to the flesh” (3.19).
Far from reporting that Jesus had even half-siblings, Eusebius repeatedly employs distancing expressions for them, and parallels Joseph’s and James’ respective familial ties to Jesus.
There are also interesting references to Simeon, where we read that, because his father Klopas was Joseph’s brother, he is “said to be” the saviour’s cousin (3.11): saying later that Klopas is Jesus’ “uncle” (3.32), and Simeon is Jesus’ “cousin” (4.5). Thus, Eusebius bases Simeon’s relationship to Jesus upon Joseph, not upon Mary: he explicitly uses designations such as “father”, “uncle”, and “cousin” for relationships which he states have no blood connection, and thus his usage of “brother” cannot be logically read as implying a blood connection.
Eusebius does not say that Mary had other children.