Đại Việt sử ký tiền biên: Ngô Thì Sĩ and the poisoning hypothesis
Ngô Thì Sĩ wrote his history in the eighteenth century; it was printed posthumously in 1800. What it is, how it survives, and the hypothesis it adds.
History and sources
Ngô Thì Sĩ (1726–1780) wrote the Tiền biên and the Việt sử tiêu án. His poisoning hypothesis is the fourth reading — a later interpretation, not record.

Ngô Thì Sĩ is the historian behind the series' fourth reading. He did not write the record; he read it, doubted part of it, and proposed something the record does not contain. His page belongs in the history section because the argument over 1009 is itself part of the history — and because his two books show how a later reader turns a gap into a hypothesis.
Ngô Thì Sĩ lived from 1726 to 1780. He wrote the Đại Việt sử ký tiền biên, a history in seventeen quyển running from the legendary period to the end of Ming rule, and the Việt sử tiêu án, a collection of judgements on the chronicle. The Tiền biên was revised by his son, Ngô Thì Nhậm. It was first printed in 1800, twenty years after its author's death, in the Cảnh Thịnh era of the Tây Sơn dynasty; the original print is reported lost, and surviving copies are early Nguyễn reprints.
That posthumous printing is not a footnote. It is the reason the series says the Tiền biên was “printed in 1800” rather than published by its author, and it is why the book belongs to a later layer of the record.
His reading of Lê Long Đĩnh's death makes two moves. First, he calls the epithet “Ngọa Triều” vulgar and baseless — a judgement on the nickname the chronicle explains by hemorrhoids and lying court. Second, he records an older question, introduced with “Có người hỏi…” (“someone asked…”): perhaps the Lý family, when the king was ill, had him poisoned and concealed it, so the histories did not record it.
The distinction is precise: the poisoning is a recorded hypothesis, introduced as a question, with no contemporary evidence. It names the Lý family, not Lý Công Uẩn personally. The series labels it as an inference written nearly eight centuries later, and keeps it in the Tiền biên rather than the Toàn thư.
The Việt sử tiêu án is also where the later verdict on Phạm Cự Lạng comes from. Ngô Thì Sĩ condemns the general who rallied the troops for Lê Hoàn in 980, in a couplet that asks why, if others risked their lives for the realm, Cự Lạng endorsed a treacherous design. It is a moral judgement written in the eighteenth century, and the page on Phạm Cự Lạng treats it as such.
Reading the two judgements together is useful. The same historian who doubted the official nickname of one king also condemned a general for siding with the man who replaced the dynasty. He is not neutral; he is a later reader with a moral programme, which is exactly what the series says later readers are.
He is the fourth reading of 1009. The site's history section stages the main text, the folk note, Ngô Thì Sĩ and the campaign record side by side, and none is confirmed. Season III's question — “A tyrant — or a victim of the victor's pen?” — is his question in dramatic form, even though he wrote it as a moral warning rather than a plot twist.
The series does not solve the question with him, and this page does not either. His value is that he shows the record being argued with, centuries before the drama arrived.
It does not assert that he proved a poisoning, that he printed the Tiền biên himself, or that he was contemporary with the events. It does not give page numbers for the passage, and it does not claim he wrote every word, since his son revised the work and later editors printed it. It does not turn his hypothesis into fact, and it does not treat his moral verdicts as the record's.
Because the series argues that the record is made by its readers as well as its writers. Ngô Thì Sĩ is the clearest case: a man writing seven hundred years after 1009, whose doubt about a nickname became one of the four readings the drama stages. The page is a note on how the past is re-argued — and on the distance between “someone asked” and “it was so”.