At any rate, the incontrovertible facts of the Vinland voyages are that Leif and Thorfinn were historical characters, that they visited, in the early part of the 11th century, some part of the American continent south-west of Greenland, that they found natives whose hostility prevented the founding of a permanent settlement, and that the sagas telling of these things are, on the whole, trustworthy descriptions of actual experience.
Lastly, there is the incontrovertible fact that Amidis de Gaula exists in Castilian, while it remains to be proved that it ever existed in Portuguese.
Among his pamphlets are A Candid Examination of the Mutual Claims of Great Britain and the Colonies (1775); Historical and Political Reflections on the Rise and Progress of the American Rebellion (1780); Cool Thoughts on the Consequences to Great Britain of American Independence (1780); and The Claim of the American Loyalists Reviewed and Maintained upon Incontrovertible Principles of Law and Justice (1788).
The duration of the reigns in several dynasties is fairly well known from the incontrovertible evidence of contemporary monuments.
The rest sat on, discussing the constitution, drawing up lists of damnable heresies and of incontrovertible articles of faith, producing plans for the reduction of the army and demanding - consolidating his rule and power.
It by no means follows, however, from this incontrovertible evidence that the acquisition either of the jaw or of the lateral fins had not been in itself an extremely gradual process.