Antiquaries had been aware of what we now call ‘crop marks’ for some 400 years before aerial photography came of age. John Leland, visiting Silchester in 1540, recorded the fact that ‘in certain partes of the ground withyn the waules’, the corn suddenly ‘decayith’ just as it begins to ripen. Leland does not seem to have understood the reason for this sudden withering, whereas William Camden, writing in his Britannia some 50 years later, recorded ‘what the inhabitants of this place told me’, viz that ‘it had been a constant observation of theirs that though the soil here be fat and fertile, yet in a sort of baulks that cross one another, the corn never grows as thick as in the other parts of the field; and along these they imagine the old streets of the city to have run’. John Aubrey was the next antiquary to record the phenomenon, again at Silchester, though he did not observe it himself; instead he informs us that ‘two learned prelates’ (thus unlikely to be making it up) ‘did affirm that one might discern in the corn-ground the sign of streets, passages and also of hearths’. The frequency of such observations grows ever more numerous as the centuries wear on, so that by the 19th century, crop marks are presented as a matter fact by Romantic poets celebrating the mark of the past upon the land. The first volume of poems composed by Jane Austen’s contemporary Mary Russell Mitford (1787-1855) and published in 1811, described:
That land where once a city fair
Flourished and pour’d her thousands there,
Where now the waving cornfields glow
And trace the wide streets as they grow
Oh chronicle of ages gone…
John Kenyon (1784-1856) was struck by the same thought and wrote, in a poem called ‘Silchester’ (1838):
