Antonio is the father of Proteus. Antonio meets with Panthino at Antonio's house to talk of his son. It seems that some others think Proteus should be doing more as a boy, and not be kept so close to home. Panthino suggests that Antonio send Proteus to Milian after Valentine, and Antonio likes the idea.
Proteus enters reading a love letter from Julia, but he doesn't want to show his father in case his father takes exception. Proteus makes the excuse that he would love to be of with Valentine, and coming on the heels of Panthino's suggestion, Antonio takes up the bluff.