The epigram (from Martial, Epigrams 12.84.1-2) can be translated:
I was unwilling, Belinda, to ravish your locks; but I rejoice to have conceded this to your prayers.Belinda's name has been substituted for Martial's Polytimus. In the 1714 edition a motto from Ovid (Metam., viii, 151) was used:
A tonso est hoc nomen adepts capillo
The "Mrs." (used in the dedicatory letter to the poem) serves to indicate that Arabella was neither a child nor a prostitute (the two groups of females designated by the word "Miss"). She was in fact twenty-two and single at the time Lord Petre cut off a lock of her hair, the event which served as the basis for the poem.
John Caryll (or Caryl), a close friend of Pope, asked Pope to write the poem to help reconcile the Fermor and Petre families. To learn more about the reason for the rift between the families, visit the event.
Beau--"Man of dress; man whose great care is to deck his person." Birthnight--(second definition)--"Evening and night of a birthday; time at which the festivities of a birthday come to a climax." (Johnson's Dictionary)
A card game for three that figures prominently in Canto III (27-104).