Those present, including many senior cardinals were stunned into silence. Nobody expected it; but nobody ever does.
The question on everyone's lips is what is the precedent this sets for future popes. But as those who look not at Old but at New Rome, the imperial city of Constantinople, the question would be rather different. Heads of what became known as the Orthodox church often retired, and the seasoned viewer knows that they never really chose to spend their old age in 'monastic perfection' (as one optimistic Byzantine chronicler puts it) - and as Pope Benedict himself is not set to do. It was a case of jump or be pushed.
In the Pope's case, there can be no question that physical frailty has played a part in magnifying concerns that must already have been overwhelming. But the real question is what was the issue (or issues?) that ground Pope Benedict down and where he was able to admit, in an act of profound humility, that he was not able to provide clarity of leadership?
Was he, as a highly intelligent scholar, simply unable to decide between two competing views; or was there hostility to his conclusions from some of those cardinals who sat in silence as the Pope announced his news. Perhaps the comment that his decision was one that had 'great importance for the life of the church' is to be understood best as a pointer at those who had not stood alongside him when he most needed their support.
As was always the case in Constantinople, the choice of successor will reveal what was really going on behind the scenes;