Though his absence from the 1958 conclave did not make him ineligible – under Canon Law any Catholic male who is capable of receiving priestly ordination and episcopal consecration may be elected – the College of Cardinals usually chose the new pontiff from among the Cardinals who head archdioceses or departments of the Roman Curia that attend the papal conclave.
New pontiffs are chosen from Cardinals who head what?
archdioceses or departments of the Roman Curia