This article examines a short passage in the Letter of Barnabas (16:3-4) which appears to refer to a rumoured, planned, or actual contemporary rebuilding of the Jerusalem Temple under Roman auspices. I identify a possible historical context and set the possible attempted reconstruction of the Temple in the framework of Roman policy relating to colonies and indigenous temples. In particular, I reject attempts to date Barnabas from a cryptic apocalyptic quotation (4:4-5), preferring to rely mainly on an apparent reference to 4 Ezra, datable to ca. 100 ce. Combining this approach to dating with a search for possible historical contexts leads me to opt for a Hadrianic date, specifically during the planning of the Roman military colony of Aelia Capitolina, for the actual or, more likely, planned/rumoured reconstruction of the Temple.