The inscription 'Dionira a presen[tato] la fatatta camisa' translates as 'Deianeira presented the fatal shirt', and relates to the moment when Hercules is presented with a poisoned shirt. The depiction of the story appears to differ slightly from Ovid's account, as here the shirt is presented by Deianeira or one of her female attendants. In Ovid's Metamorphoses, Lichas, a messenger, gives the shirt to Hercules as a gift from Deianeira. She was unaware that the shirt was smeared with poison rather than a love potion,1 and the shirt killed Hercules by causing his skin to corrode and burn.
See Johanna Lessmann, Italienische Majolika, Katalog der Sammlung, Herzog Anton Ulrich-Museum, Brunswick, Brunswick, 1979, pp. 343-344, nos. 482-485 for pieces which are almost certainly by the same hand.
1. Earlier Nessus the centaur had attempted to ravish Deianeira while he was ferrying her across a river. Hercules had already reached the other riverbank and he fired an arrow at Nessus. Once hit by the arrow, Nessus knew his blood was poisoned with the hydra's gall, and as he was dying he cunningly advised Deianeira that she should collect his blood and use it as a love potion.