The received text of Antiquities 20.9.1 (often numbered 20.200) describes James’s execution and calls him the brother of Jesus “who was called Christ.” A few lines later, it says Jesus son of Damneus was made high priest. This site treats the Christian-Jesus identification as an interpolation and reads the passage in that full context.
The mythicist reading
Without the Christian identification, the nearby appointment of Jesus son of Damneus offers a contextual referent for James’s brother. “Christos” can mean “anointed,” a term that fits a high priest; the passage does not independently establish that James was related to the Christian Jesus.
The strongest reply
The counterargument is that the received Greek manuscripts contain the phrase and that, if it is original, readers may identify this Jesus with the Christian figure. Many scholars accept the passage as substantially authentic. That reading still depends on the wording being original and on how the Damneus sequence is interpreted.
Where the evidence leaves us
The received phrase does not settle its own authenticity or referent. The textual claim, the surrounding appointment of Jesus son of Damneus, and the transmission history all matter.