What is the birthday of the Argentine defender Associazione Sportiva Roma signed before the 2001 season?
2000–01 A.S. Roma season:  Important signings were the Argentines Walter Samuel, a defender, and Gabriel Batistuta, a top striker. Walter Samuel: Walter Adrián Luján Samuel (] ; born Walter Adrián Luján; 23 March 1978) is a retired Argentine professional footballer.
23 March 1978