20 May 1957
stated · probable
Source
derived from the event's own title: "Neville's lecture of May 20, 1957"
Reasoning
The event held NO date claim of any kind; its own title states 1957-05-20 (day precision, parsed as "month day year"). ⚠ A title in this corpus is a DERIVED artefact — an earlier pass wrote it from the passage text — so this claim is title-derived and is marked as such rather than cited as a source document; the underlying text remains the real evidence and would supersede it. Confidence `probable`, never `certain`, for that reason. Precision is never inflated beyond the title's own wording. CALIBRATION (run v1.1/l1.4/titledate, against the 489 events that already hold an independent preferred date): day 96.1%, month 94.1% agreement. Titles naming a REFERENCE event rather than the event itself ("before", "after", "during the week of", "per ... lecture") are refused outright and never reach this write — reading an anchor as the date is the same laundering phase3b committed when it wrote telling dates onto events.
