Daughter of Simonides, mother of Marina. Thaisa expects to marry whoever wins the jousting contest in Pentapolis. She is very impressed with Pericles, and writes to her father that she wants to marry him. Simonides sends away the other knights and challenges Thaisa, saying that Pericles is not a good catch since they don't know his lineage. She insists she will have him, and they are married. Later, at sea with Pericles on the way back to Tyre, Thaisa gives birth to Marina but seems to die during the birth. She is tossed off the boat in a wooden chest, but is later discovered and revived in Ephesus by Cerimon. She becomes a priestess in Diana's temple in Ephesus.