That was "the date on which Lincoln asked to be released from his engagement to Mary Todd".
Simon explains that the various reasons the engagement was broken contradict one another.
Attention to the sexuality of public figures has been heightened since the gay rights movement of the later 20th century.
Lincoln, Baker discounts the criticism of the marriage.
She says that contemporary historians have a basic misunderstanding of the changing nature of marriage and courtship in the mid-19th century, and attempt to judge the Lincoln marriage by modern standards.
Time magazine addressed the book as part of a cover article by Joshua Wolf Shenk, author of Lincoln's Melancholy: How Depression Challenged a President and Fueled His Greatness.
Shenk dismissed Tripp's conclusions, stating that arguments for Lincoln's homosexuality were "based on a tortured misreading of conventional 19th century sleeping arrangements". Chesson welcomed the historical significance of Tripp's work, and commented that - though not conclusive - "any open-minded reader who has reached this point may well have a reasonable doubt about the nature of Lincoln's sexuality".
Lincoln is believed to have suffered something approaching clinical depression.