Who is Thaisa from Tales from Shakespeare and what is their importance?

Thaisa is Pericles's wife. When she seems to have died during childbirth on board Pericles' ship, Pericles places her body in a large chest filled with jewels, sweet-smelling spices and a note. Eventually, the chest ends up on shore, and Ephesus, who discovers the chest..... also finds Thaisa..... alive.