Who was the Roman queen of the underworld, married to Pluto?

The Roman queen of the underworld, married to Pluto, was Proserpina.

Proserpina was the Roman goddess whose mythology closely parallels that of the Greek Persephone. She was the daughter of Ceres and became queen of the underworld after Pluto carried her away and took her as his consort. Roman writers also refer to the underworld ruler as Dis Pater or Orcus in different traditions.

Her most famous story explains the seasons. Ceres’s grief over her daughter’s disappearance caused crops to fail and the earth to become barren. Because Proserpina had eaten pomegranate seeds in the underworld, she could not remain permanently among the living. She therefore spent part of the year below and part above, allowing the earth to return to fertility.

Proserpina is sometimes confused with Venus, Diana, or Juno because all are prominent Roman goddesses. Their roles differ sharply: Proserpina governs the underworld and seasonal renewal, while Ceres is the agricultural mother who searches for her.