The story of Lot and his daughters is told in Genesis XIX, 33-5. Fleeing the destruction of Sodom and Gomorrah, Lot’s wife disobeys the divine will, looks back, and is turned into a pillar of salt. Taking refuge in a cave, Lot's daughters believe that their father is the last surviving male. To secure the future of the human race, therefore, they get him drunk and seduce him. This rather unsavoury story was very popular with Baroque artists, often for less than pious reasons - it offered a saucy seduction scene with an impeccable Biblical pedigree.
Franceschini, trained by Cignani, ensured the survival of the Bolognese classicist style well into the 18th century. Like his master, he was extremely successful in his day.