On Thursday, September 28, the Pope sat down to dinner in his Vatican apartment with his two secretaries, the Italian Father Diego Lorenzi and the Irishman Father John Magee. It was a simple meal – clear soup, veal, fresh beans and salad.

The secretaries had a glass of wine each; the Pope drank only water. When it was over, the three briefly watched a news programme; then, soon after nine, John Paul I retired for the night, setting his old wind-up alarm clock for the hour at which he normally rose, 4.30am.

The next morning at exactly that time a nun named Sister Vincenza carried a flask of coffee to his study, as she had done every day for 20 years since his time in Vittorio Veneto, knocking at his bedroom door and bidding him good morning. Most unusually, there was no reply. A quarter of an hour later she returned and knocked again. Still no sound.

By now seriously alarmed, she gingerly opened the door. There was the Pope sitting up in bed, wearing his spectacles and with some sheets of paper clutched in his hand. She felt his pulse. There was none; the wrist was icy cold. Panic-stricken, she rushed to wake Lorenzi and Magee, who immediately telephoned the Secretary of State, Cardinal Jean Villot, in his apartment two floors below.

Villot took matters in hand. It was now 5am. First he telephoned two or three of his senior colleagues; then he called the papal morticians and embalmers, the Signoracci brothers, telling them that an official car would be leaving at once to collect them and bring them to the Vatican.

Finally, having forbidden any of those present to say a word to anyone until he gave them permission, he summoned the deputy head of the Vatican’s health service, Dr Renato Buzzonetti.

Buzzonetti had no idea of the Pope’s medical history; as he himself admitted, ‘the first time I saw him in a doctor/patient relationship he was dead’.

Nevertheless, after the most cursory of external examinations he unhesitatingly diagnosed a heart attack, putting the time of death at about 11pm.