Since the founding of Dartmouth College, literary interest has been strong amongst its students, and as soon as Dartmouth had reached sufficient size, literary societies began to form. In the late 18th century times were indeed hard in Hanover.  The opportunity to share books, to have good conversations, and to find critical review for one's literary works, were appreciated by the student body.  For these reasons, groups were formed to promote literary excellence.  Alpha Delta was one of the first groups, and although the size of the group was small, it had outstanding leadership, and accomplished much good work.

There was an Alpha Delta Society at Dartmouth as early as 1799.  It was known as the Literary Adelphi, the Adelphian Society, or the Alpha Delta Society.  This group was formed to promote literary excellence among its members.  They set up a common library, and enjoyed extemporaneous speeches given each week.  A highlight of their work was a series of annual addresses given before each graduation exercise.

During the late 18th century, the College recognized four societies.  These were Phi Beta Kappa, the Social Friends, the United Fraternity, and the Theological Society.  Alpha Delta was a reluctant member of the United Fraternity, because the College prohibited membership in any society other than the four recognized ones. Alpha Delta was formed because the larger societies did not provide an effective opportunity for public debate, nor did they offer an opportunity for close fraternal ties.  Known as the Independent Confederacy before their affiliation with the United Fraternity, the Dartmouth Literary Adelphi announced the formation of their society in the Dartmouth Gazetteon October 26, 1799.  Cyrus Perkins, the president, announced that meetings would be held on the first Friday of each month, and that the library would be expanded.  Due to the pressure from the rival Friends Society, however, the organization enjoyed independence for only a few years.  The College eventually banned the Alpha Delta Society.  

Neither the College nor the Social Friends, however, were able to thwart the desire for membership in this literary membership.  The Alpha Delta traditions were taken up again in 1821.  This time the society associated itself with the Antinomian and undertook its affairs in secret.  Little is known of the procedures within the organization because of the tightly maintained veil of secrecy.  It is known that weekly meetings were held for debate and literary discussions. They also gave addresses at graduation exercises.  Their medal has been preserved, however, and was a simple pendant of silver, little more than an inch square.

The Antinomian became Gamma Sigma in March 1843.  At this time, it was revealed that the outgoing president of this organization had been Professor Crosby, and his successor was to be Professor Lord, the incoming President of the College.  This change of leadership and name accompanied an enlarged role for the organization in the social arena.  In this respect, the change was a move to resemble the modern fraternity.  Now, in 1841, the modern Greek letter fraternities began to form, and employed the chapter system.  

Psi Upsilon was the first of the nationally affiliated societies on campus.  Alpha Delta Phi was the second, formed in 1846.  It was formed by the sophomore members of Gamma Sigma, who had formed the Tau Delta Theta fraternity in 1843.  With the assistance of the Yale and Amherst chapters of Alpha Delta Phi, the acceptance of Tau Delta Theta into the national organization of Alpha Delta Phi was arranged.  In March of 1846, the installation took place in Professor Sanborn's office.  There the charter was produced and signed, and the Dartmouth Chapter of Alpha Delta Phi was created.