Catholic is the true target in The Merchant of Venice, covered by the apparent anti-Semitism.
The name Portia is selected, for Port- matched with the front of Protestant.
Shylock is created based on the tail of Catholick. The tail should follow the front.
Nerrissa, Portia's gentlewoman, provides the letters to complete (the gentle) Protestant.
Lancelet, Shylock's clown servant, fulfills Catholick.
The hint is at the end, "He presently become a Christian." Presently has the definition of "so as to be, or as being, present; in presence" (OED 1, 1579). The role Shylock presents himself a Christian in the play.
Protestant Pisanio vs. Catholic Cloten
Protestant Prospero vs. Catholic Caliban