While for a time he continued to lecture in both England and Ireland, and wrote an autobiographical account including his marriage, which sold well, he and his family eventually fell into obscurity and near-poverty.

There was no school for colored children in Fort Monroe, but he received some informal education from Federal soldiers, including some French and German.

[1]: 1–5  A teacher recommended him to Gerrit Smith, a wealthy abolitionist and philanthropist, whose help, along with that of Lewis Tappan,[7]: 89  made it possible for Allen to attend the Oneida Institute.

[10]: 44 At Oneida, like most college students at the time, William received what in the 20th century would be called ministerial training: Hebrew, Biblical Greek, theology, and philosophy, with small amounts of science, algebra, and public speaking (declamation).

[12] Together with Henry Highland Garnet, also an Oneida alumnus, he edited and published the abolitionist newspaper National Watchman, in which "the selections and editorials show that he [Allen] is a man of sense, education, and good temper".

[1]: 40  When it ceased publication in 1847,[14] Allen moved to Boston, studying under and working as a clerk for the abolitionist lawyer Ellis Gray Loring.

In 1850 Allen, who had begun to enjoy fame as a lecturer (see below), was appointed professor of Greek and Rhetoric at New-York Central College (NYCC) in McGraw, New York.

[6]: 3 [21]) Since his predecessor Charles L. Reason had departed earlier in 1852, he was in 1852 and 1853 "the only acting colored Professor in any college in the United States", in Frederick Douglass' words.

[22] Allen voted (for Franklin Pierce) in the 1852 United States presidential election, since poll workers thought he was white.

It was not until Frederick Douglass's marriage to Helen Pitts in 1884 that a married white–black couple could live openly in Washington, D.C., without violence, although they received much vituperation.

[7]: 91 According to a resolution passed in February, 1853, at a state convention of the Liberty Party in Syracuse, New York, "the recent outrage upon that accomplished and worthy man, Prof. Wm.

'The probable destiny of the African race', &c. &c." A letter from Lord Shaftesbury said he "sympathises most heartily with Professor Allen, and sincerely wishes him success in his undertaking.

It will give Lord Shaftesbury great pleasure to assist in any way that he can a gentleman of the coloured race, who is a hundred times wiser, and better, than his white oppressors.

"The lecture was one which would have done honor to the mind of the historian Bancroft, while the gentle and modest demeanor of the speaker, together with the gracefulness of his elocution and ready command of language, gave to the performance an additional interest," said the Essex County Freeman.

[45] The Syracuse Daily Standard called him "a colored gentleman, of brilliant talents, and education", and said that his lecture "was one of the best ever delivered in this city".

"One individual who had never been known to express any favorable feeling for the colored man and his cause, on leaving the lecture room the other evening confessed that the impression made on him by the subject as presented had given him new and exalted opinions of the class hitherto deemed so inferior.

"[47] When based in Boston (1847–1850), at New-York Central College (1850–1853), and in England and Ireland (1853–), nearly the whole of which he visited,[9]: 32  he was a frequent speaker, making small trips to the venues where he was to speak.

[53] Allen "seemed indeed to be perfectly familiar with every branch of the human family, as far back as the days of Noah, and to possess an intimate acquaintance with all the writings extant of every historian, both ancient and modern.

Proceeding in his lecture, Mr. [A. ran] a tilt against Prof. Agassiz, who has recently made an attack upon Divine Revelation, by denying that 'God made of one blood all nations of men to dwell on all the face of the earth,' and completely unhorsing him, knocked him back into the Dark Ages to flounder on through the chaos of his own conflicting opinions with Linnæus, Buffon, Helvetius, Monboddo and Darwin—men who once advocated the same absurd theory, that the human race originated from different sources.

"[45] "Mr. Allen commenced with the somewhat startling assertion, that the Africans originated the arts and sciences [in Ethiopia] and gave the first impulse to civilization.

These traits are contrasted with those of the "Anglo-Saxon race", which are "physical force, calculating intellect, daring enterprise, and love of gain".

The greatness of the American nation is, unquestionably[,] owing ["owning" in the original] no less to the various elements of which it is composed, than to its climate and favorable circumstances.

[55][44] Professor Allen then proceeded with his lecture, and from the eloquence and learning which he displayed in dealing with the subject appeared to take the audience completely by surprise.

He took a Scriptural view of the origin of the Ethiopians, Egyptians, and other races of ancient Africa, arguing that they were descended from the four sons of Ham; and showed from classic authority the high civilisation to which they had attained when Greece was yet barbarous, and before Rome arose.

There was scarcely a race, he showed, on the face of the earth, which had not declined in intellectual power and physical beauty under the same influences, and in the mediæval ages, when Englishmen were sold as slaves, they were described by their purchasers, the Irishmen and Romans, as ugly and stupid.

The lecturer then dwelt more particularly upon the leading characteristics of the African race, their religious tendency, and the predominance of the moral over the intellectual in their character—the affeetionateness of their disposition, their love of humour, &c. He gave many weighty hits at Anglo-Saxon civilisation, which told well with the audience, who appeared very much delighted.

When we look at Douglass and others, who, under a mountainload of difficulties, have struggled and risen to their present eminence, we cannot but feel how many noble intellects and exalted spirits of which the world has had no cognizance, have been murdered by this great but rapacious Republic.

[57]He "illustrated the condition of the nominally free colored American—his disabilities in the various states of the Union—also the prevalence and force of that vulgar prejudice which had been so truthfully delineated.

"[58] In England and Ireland, he spoke about his barely escaping lynching, and having to exile himself, because his skin was the wrong color to marry a white young lady.

"Prof. Allen, of New York, gave the audience account of the aristocracy of complexion as established by custom in America, and of the dangers he had incurred, because be had ventured to think and act for himself, without regard to such a regency.