Pope after pope has been aware that something must be done.
An ancient problem, worsening each year: the calendar
Is straying from the sun. The vernal feast of Easter drifts
By tiny steps away from spring, towards the days of heat.

Pope Gregory is in his study with astronomers.
Their chief is Clavius the Jesuit, whose voice escapes
His lifetime’s training in restraint. ‘The remedy is here,
Your Holiness,’ (he drums a paper) ‘by God’s help, at last.’

Pope Gregory’s left hand shifts slightly. He is listening.

‘Cut ten days from 1582,’ says Clavius.
‘Observe the saints’ days lost the day before or after. Then,
In three of every four years which conclude the centuries
To come, omit the leap year. But retain the extra day
In 1600, and the year 2000, and so on.
The leap year (brainchild of an older Roman!) was indeed
A fine invention in its time, though not quite fine enough.’
He pauses for effect. ‘Thus will the calendar remain
Obedient to the sun for longer than three thousand years.’

Pope Gregory is satisfied. ‘Prepare a Bull,’ he says,
‘And show me when it’s written. Thank you, Christoph, gentlemen.’

The Bull is posted on the internet. I’m reading it
On leap year day 2000. It contains this very date,
The day that I am living in, foreseen, committed to:
An act of faith in reason… History unmakes itself,
The known reverts to the unknowable, and Clavius
Is pointing out to Gregory a detail in the text.

‘Your Holiness, the Day of Wrath may intervene before
The date here written. In that case, Almighty God will see
We have not sought to hasten His return before His will.’

The Pope is thinking that the wisdom of astronomers
(And Jesuits) has not always been welcome to the Church,
But says aloud, ‘We wish it to be printed. Bring our seal.’