I never knew Castelnuovo personnally. But once again a memory of Professor Baker, almost an exact contemporary of Castelnuovo, comes back to me. Baker and Castelnuovo, met when the latter attended the International Congress of Mathematicians in Cambridge in 1912. Baker, who was somewhat shy of revealing personal feelings, and usually restricted his praise of people to praise of their mathematical achievements, made an exception of Castelnuovo and frequently told me in later years of the intense pleasure he had found in Castelnuovo's company.
W.V.D. Hodge (Atti del Simposio internazionale di geometria algebrica, Roma 1965)
Nell'agosto 1912 Castelnuovo partecipa al V Congresso internazionale dei matematici tenutosi a Cambridge.