Lancelot was a writer at once voluminous and lively. In the latter part of his life he produced several treatises on theological subjects, the most popular of which was called _An Introduction to the Sacrament_. This book passed through many editions. The doctrine it contains leans rather to the Low Church side. But much the most characteristic of his writings were his works on Mahommedanism and Judaism, the results of his studies during his residence in Barbary. These show not only considerable industry and research and powers of shrewd observation, but that genuine literary faculty which enables a writer to leave upon a subject of a general nature the impression of his own character. While there is nothing forced or exaggerated in his historical style, a vein of allegory runs through the narrative of the _Revolutions of the Kingdoms of Fez and Morocco_, which must have had a piquant flavour for the orthodox English reader of that day. Recollections of the Protectorate would have taken nothing of its vividness from the portrait of the Moorish priest who "began to grow into reputation with the people by reason of his high pretensions to piety and fervent zeal for their law, illustrated by a stubborn rigidity of conversation and outward sanctity of life." When the Zeriffe, with ambitious designs on the throne, sent his sons on a pilgrimage to Mecca, the religious buffooneries practised by the young men must have recalled to the reader circumstances more recent and personal than those which the author was apparently describing. "Much was the reverence and reputation of holiness which they thereby acquired among the superstitious people, who could hardly be kept from kissing their garments and adoring them as saints, while they failed not in their parts, but acted as much devotion as high contemplative looks, deep sighs, tragical gestures, and other passionate interjections of holiness could express. 'Allah, allah!' was their doleful note, their sustenance the people's alms." And when these impostors had inveigled the King of Fez into a religious war, the description of those who "mistrusted their own safety, and began, but too late, to repent their approving of an armed hypocrisy," was not more applicable to the rulers of Barbary than to the people of England. "Puffed up with their successes, they forgot their obedience, and these saints denied the king the fifth part of their spoils.... By which it appeared that they took up arms, not out of love for their country and zeal for their religion, but out of desire of rule." There is, indeed, nothing in these utterances which need have prevented the writer from consistently promoting the Revolution of 1688; yet his principles seem to have carried him far in the opposite direction; and it is interesting to remember that the assertor in Convocation of the doctrine of indefeasible hereditary right was the father of the author of the _Whig Examiner_ and the _Freeholder_.