Antonietta Meo (15 December 1930 – 3 July 1937), nicknamed "Nennolina", was an Italian girl who died of osteosarcoma.

[2] She attended Catholic schools as an active, charismatic girl who led playmates in many games even after falling ill, being well-liked for her kindness.

[3] Meo was diagnosed with osteosarcoma at five after she fell and injured her knee, and the injury didn't heal.

Catholic theologians have called her a "mystic" because the six-year-old wrote "extraordinary" letters to Jesus Christ in her last months.

[9] Meo insisted on writing one last letter to Jesus a few days before her death but failed to finish it due to her illness.

After Meo died, her mother received a vision of her daughter in a glorified state, reassuring her that she was now in heaven.

[4] The Basilica of Santa Croce in Rome, where Meo was baptized and spent much of her time in meditation, holds a shrine containing relics from her life.

[12] Before 1981, the Vatican Congregation for Saints required that a candidate for sainthood reach some level of maturity.

[14] The next-youngest modern saint, Maria Goretti, died in 1902 at age eleven and was canonized in 1950 as a virgin and martyr.