In Greek mythology, Iapetus was Pandora’s father-in-law because he was the father of Epimetheus.
Pandora married Epimetheus, and Epimetheus was one of the sons of the Titan Iapetus. This makes Iapetus part of Pandora’s extended family in genealogical traditions, even though he is not a central participant in the opening of the container.
Iapetus was one of the twelve Titans in Greek mythology. His other famous sons include Prometheus, Atlas, and Menoetius, making Pandora’s marriage connect her to several major figures in Greek myth.
Genealogies can differ between ancient authors and later summaries, but the relationship through Epimetheus is a standard one in accounts based on Hesiod. Iapetus should not be confused with Cronus, who was the father of the first generation of Olympian gods.