In Ariosto’s epic poem Orlando Furioso, the noble knight Orlando is driven mad by jealousy. Eventually, his friend, the English knight Duke Astolfo, travels to the Moon to recover Orlando’s lost wits. The Orlando Furioso was scientist Galileo Galilei’s favourite poem. Did it help him with his astronomical discoveries? Let’s look at Astolfo’s journey more closely.


I. First stage: the hippogriff

In canto 34 Astolfo finds himself travelling across North Africa upon a hippogriff. The hippogriff, or ‘griffin horse’, was a cross-bred beast ‘gotten of a griffin and a mare,/And like a griffin had the former part,/As wings and head and claws that hideous are/. . . But all the rest may with a horse compare.’ 1

Coming to a hill ‘whence Nilus first doth fall,/If so that Nile have any head at all’, Astolfo mounts his flying steed. ‘So cutteth he the air and does not stop/Till he was come unto that mountain’s top’. The mountain was so high that it ‘nigh touched the circle of the Moon’. In other words, it was very close to the boundary between the terrestrial and celestial realms of the cosmos.

It turns out that Astolfo has in fact arrived at Paradise on Earth, or ‘Paradise Terrestrial’, ‘the sweetest place that ever man beheld’:

The trees that there did grow were ever green;
The fruits that thereon grew were never fading;
The sundry-coloured birds did sit between
And sing most sweet, the fruitful boughs them shading;
The rivers clear as crystal to be seen,
The fragrant smell the sense and soul invading.

Here Astolfo is greeted by St John the Evangelist.2 The saint explains that Astolfo has been summoned thither so that he ‘may be taught/How to his wits Orlando may be brought’. Fortunately, the Apostle can also provide the means to complete the task.

II. Second stage: the fiery chariot

The next morning St John wheels out Elijah’s fiery chariot. Harnessing ‘four horses fierce, as red as flaming fire’, they set off together through the uppermost terrestrial realm, that is, the realm of fire, the lightest and therefore highest of the terrestrial elements. Fortunately, ‘although the fire were wondrous hot,/Yet in their passage they no heat did feel,/So that it burned them nor offends them not.’ Thus they pass into the celestial realm of the Moon.

Here they encounter a problem more philosophical than pyrotechnical. According to the dominant cosmology of Ariosto’s (and Galileo’s) day, there was a strict separation between the Heavens and the Earth. There was supposed to be a categorical difference in their very substance. On the one hand, Earth is the realm of the four terrestrial elements: earth, water, air and fire, which are forever striving to separate themselves out into four concentric spheres according to their relative heaviness or lightness. Earth is therefore the realm of constant change. The Heavens, on the other hand – the celestial spheres of the Sun, the Moon and the other planets, and the stars – are made of a fifth element. This crystalline quintessence is perfect and unchanging (apart from the constant, perfect circular motions of the celestial bodies).

The Moon, therefore, has to be a perfect, immaculate crystalline body. And, at first, Astolfo observes that ‘The Moon was like a glass all void of spot/Or like a piece of purely burnished steel’. So far so conventional. But then Astolfo takes a closer look at the Moon and

 ‘Twere infinite to tell what wondrous things
He saw that passed ours not few degrees,
What towns, what hills, what rivers, and what springs,
What dales, what palaces, what goodly trees.

The Moon, in other words, was not the perfect crystalline sphere of conventional astronomy, but really very much like the Earth. And there, in ‘a storehouse strange’, Astolfo finds Orlando’s lost wits, as previously described. In due course he returns to Earth and returns the lost wits to their owner. Thereby he saves Christendom from the Saracen.

III. Galileo and the Moon

Half Moon, NASA, on Unsplash

In 1610, more than 20 years after the events chronicled in Galileo’s Revenge, Galileo turned his new telescope upon the Moon. In particular he studied the shifting boundary between the sunlit and the shadow areas as the Moon waxed and waned. ‘The boundary dividing the bright from the dark part,’ he observed, ‘does not form a uniformly oval line, as would happen in a perfectly spherical solid, but is marked by an uneven, rough, and very sinuous line.’ Consequently, he concluded ‘the surface of the Moon to be not smooth, even, and perfectly spherical, as the great crowd of philosophers have believed about this and other heavenly bodies, but, on the contrary, to be uneven, rough, and crowded with depressions and bulges. And it is like the face of the Earth itself, which is marked here and there with chains of mountains and depths of valleys.’

Galileo went on to remark that the intrinsically darker areas of the Moon – now, indeed, known as ‘mare’ or ‘seas’ – ‘are not seen to be filled with depressions and prominences, but rather to be even and uniform’. And, thus, he suggested, ‘if anyone wanted to resuscitate the old opinion of the Pythagoreans that the Moon is, as it were, another Earth, its brighter part would represent the land surface while its darker part would more appropriately represent the water surface.’

Beyond that Galileo does not go: there is no suggestion of ‘palaces . . . goodly trees’. Maybe he lacked the fantastical imagination, or maybe he was already alert to the theological complications of populating such an inaccessible realm with human souls? But either way, it is tempting to think that he was encouraged in his speculations by Astolfo’s trip to the Moon as described in his favourite poem, Orlando Furioso. In the words of Ariosto, however

  . . . more of this hereafter I will treat,
For now this book begins to be too great.

IV. Further reading

Ludovico Ariosto, Orlando Furioso. I have used the rather free translation ‘into English heroical verse’ by Sir John Harington (1560-1612). There is a handy book of Selections from this edited by Rudolf Gottfried (Indiana University Press, ca.1963).

Galileo Galilei, Sidereus Nuncius, or The Sidereal Messenger, translated with introduction etc. by Albert van Helden (Macmillan, 1960). If you want to read some of Galileo’s own writings, there is no better place to start.

Marjorie Hope Nicolson, Voyages to the Moon (Macmillan, 1960). A delightful exploration of the literary genre throughout history.

  1. Given that the griffin itself is ‘a fabulous animal having the head and wings of an eagle and the body and hindquarters of a lion’ [OED], this is altogether quite a mixture.
  2. The Apostle is still alive, in fulfilment of the implicit prophecy in John 21:22.