Arethusa is the daughter of the King of Calabria. Not at all enamored of Pharamond, the foreign prince to whom her father has pledged her, Arethusa instead loves Philaster, the true heir to the kingdom. Accused by Megra of having illicit relations with her page Bellario, Arethusa suffers condemnation from both her father and Philaster; the latter even wounds her with his sword. Her name is cleared when Bellario is discovered to be Dion's disguised daughter Euphrasia, who in her love for Philaster assumed her page's disguise to serve him. In greatness of trust and spirit, the newly wedded Arethusa and Philaster accept the celibacy-sworn Euphrasia into their service.
BELLARIO
Actually Dion's daughter Euphrasia in the disguise of a male page, Bellario enters Philaster's service. Incognito because she loves Philaster she is promptly given the task of liaison between Philaster and Arethusa. Accused of illicit relations with the princess, Bellario is dismissed from both Philaster's and Arethusa's service. When Philaster wounds Arethusa in the woods, Bellario confesses to the crime to save Philaster. Eventually, Bellario reveals himself to Dion as Euphrasia, clearing the good name of Arethusa and embarking upon a life of service to the princess Arethusa and her husband Philaster.
CLEREMONT
Cleremont is one of the noble Gentlemen in the king's court. He is a loyal supporter of Philaster's claim to the throne throughout, and he sees the would-be heir Pharamond as a typical braggart. He is consistently in the company of Lord Dion and the gentleman Thrasiline.
COUNTRY FELLOW
This Country Fellow is an unnamed citizen who searches the woods hoping for a glimpse of the king. Observing Philaster's wounding of Arethusa, the Country Fellow comes to her aid, wounding Philaster and receiving injury himself. He would have been able to identify Philaster as Arethusa's assailant when Bellario confessed to that crime, but the Country Fellow is led away by two woodmen to have his wounds dressed and does not appear again.
DION
Dion is a Lord in the king's court and is staunchly supportive of Philaster; he is also the firm friend of Cleremont and Thrasiline. Given to philosophical commentary in greater depth than his peers, Dion nonetheless errs in believing Megra's remarks concerning illicit relations between Arethusa and Bellario. Dion claims he himself "caught" Arethusa and Bellario together and is thus the cause of Philaster's loss of faith in the princess. Dion is chosen by Bellario as "confessor" near the story's end and at that time learns that Bellario is in fact his own disguised daughter Euphrasia, thought to be away on a pilgrimage.
EUPHRASIA
Euphrasia is the daughter of Lord Dion and for most of the drama takes the role and disguise of the male page Bellario. Revealing herself at the play's finish, Euphrasia swears both an undying love for Philaster and a future celibacy. She is warmly accepted into the service of Philaster and his bride Arethusa.
GALATEA
Galatea is a wise and virtuous lady who attends the princess Arethusa in the king's court. Early in the drama Galatea establishes a clear preference for the worthiness of Philaster; she sees the would-be heir Pharamond as a "dog" and quite wittily rebukes Pharamond's sexual advances.
KING OF CALABRIA
From the start the King of Calabria is seen as something of an usurper who not only has unrightfully taken the kingdom from Philaster's father but who also plans to give both his daughter and the kingdom to the foreigner, Pharamond of Sicily. Unable to keep order in his own kingdom, the king has given in to demands of the citizens that Philaster remain a free man. Despite his errant policies, the king is concerned enough with morality to stop Megra's illicit relationship with Pharamond and to order his daughter Arethusa to dismiss her page Bellario. When he finally realizes the innocence of his daughter and the strength of Philaster's popularity, the king commits to honoring Philaster's rightful claim to the throne and offers a blessing upon the marriage of Arethusa and Philaster.
MEGRA
Though circulating among ladies and courtiers, Megra is nonetheless a bawd. She has a wide reputation for loose behavior that is matched only by the sexual suggestiveness of much of her speech. Caught almost "in the act" with Pharamond, Megra threatens to reveal what is actually a false story of illicit relations between Arethusa and Bellario. She does indeed eventually tell her tale in public, only to be banned from court when her deceit is discovered. The plot suggests that Megra may accompany Pharamond as he returns to his own country, for Philaster has offered her that option.
OLD CAPTAIN
First mentioned as an "old grey ruffian" who leads the citizens in mutiny, the Old Captain is indeed in charge of citizens who have captured the would-be heir, Pharamond. Loyal only to Philaster, the Old Captain takes bids from his countrymen for Pharamond's body parts. He is convinced to disband the citizens and release Pharamond only at the insistence of Philaster and the promise of Philaster's rightful succession to the throne.
PHARAMOND
Pharamond is the foreign prince anxious to become heir to the kingdom of Calabria and husband to princess Arethusa. On both counts, Pharamond is thrust into the place of the rightful heir, Philaster. Arrogant and self-praising, Pharamond propositions Arethusa, Galatea, and Megra before the latter consents to a liaison; the two are caught together by the king. Hated by the citizenry, Pharamond is captured and close to torture when Philaster arrives to rescue him. More than eager at this point to be quit of this kingdom, Pharamond accepts the king's gracious offer of safe conduct back to the prince's own land. The plot suggests that the lewd Megra may well accompany him home.
PHILASTER
Philaster is the rightful heir to the throne of Calabria. Though extremely popular with the citizenry, Philaster is not to be the next king. Instead, the current king has arranged for Pharamond, a foreign prince, to become king and to marry the king's daughter Arethusa. Himself in love with the princess, Philaster sends his page, Bellario, to Arethusa to facilitate their clandestine communications. Philaster is heartbroken when Lord Dion claims that he has caught Arethusa and Bellario in illicit relations. Later discovering Arethusa in the woods, Philaster wounds her. Bellario demonstrates loyalty when the page confesses to the crime to save Philaster. By the play's conclusion, Philaster has calmed the rebellious citizenry, saved Pharamond from the commoners' wrath, wed Arethusa and been promised his rightful crown. He also discovers that Bellario is in fact Euphrasia, Dion's disguised daughter who entered Philaster's service for love. She swears herself to celibacy and enters service with the newlywed Philaster and Arethusa.
THRASILINE
Thrasiline is a noble court Gentleman. He is firmly in opposition to the succession of the foreign prince Pharamond to the Calabrian crown, and he remains loyal to Philaster. His small role serves to round out a steadfast threesome of courtiers: himself, Cleremont, and Dion.