The "birth of Avisa " is explained in the introductionary poem In praise of Willobie His Avisa by Contraia Contrariis Vigilantius Dormitanus. In this Poem Avisa and Penelope are merged into one then metamorphosed into an Eagle. Metamorphoses like these were common in the writings of Ovid and Spencer. Avisa and Penelope represent one person.
There are two other examples of merged characters . The Cavaleiro is a merged character who represents both of Penelope Rich's brothers Robert and Walter Devereux.
In addition the Nobleman represents two characters. Baron Rich and Avisa's husband.
Avisa represents the two personas of the one woman - Penelope Rich.