This scene is taken from the Heroides by the Roman poet Ovid. When Cydippe went to make an offering
at the temple of Diana, Acontius, who was secretly in love with her, threw an apple inside with the following
words written on it: ‘I swear by the sanctuary of Diana that I will marry Acontius.’ Cydippe read the words
aloud, thus turning them into a solemn vow.