It was intended to be the largest cast bronze horse sculpture ever, but Leonardo da Vinci never managed to finish it.
The Sforza horse was a commission from the Duke of Milan, Ludovico il Moro, in 1482. It was intended to be in honour of his father, Francesco.
Da Vinci sweated over its design, creating many small sketches of horses intended to illustrate his notes about the complex procedure for moulding and casting the sculpture.
In 1493 – 11 years later – he presented a 7.3-metre (24-foot) clay model on the occasion of Ludovico’s daughter’s wedding, from which the bronze horse could be made.
The model was never cast in bronze. French troops attacked Milan in 1499 and destroyed the clay model, which was used by archers as target practice. In any case, the tonnes of bronze set aside for the artwork had to be used for the war effort.
While the failure to complete the horse cannot be laid entirely at da Vinci’s feet, the 11 years the accomplished artist and engineer took to design and create the clay model highlights one of his crucial shortcomings – an inability to finish his works.
The novelist Matteo Bandello, a contemporary who saw Leonardo working on the Last Supper, clearly identified his fickleness of temperament and chaotic organizational skills.
“I have also seen him, as the caprice or whim took him, set out at midday … from the Corte Vecchio, where he was at work on the clay model of the great horse, and go straight to the Grazie and there mount on the scaffolding and take up his brush and give one or two touches to one of the figures and suddenly give up and go away again.”
Drawing on such accounts, a university professor, writing in the journal Brain, suggests that the best explanation for da Vinci’s inability to finish his works is that he may have had Attention Deficit and Hyperactivity Disorder (ADHD).
Professor Marco Catani lays out the evidence supporting his hypothesis that, as well as explaining his chronic procrastination, ADHD could have been a factor in da Vinci’s extraordinary creativity and achievements across the arts and sciences.
Catani, from the Institute of Psychiatry, Psychology and Neuroscience at King’s College, London, says: “While impossible to make a post-mortem diagnosis for someone who lived 500 years ago, I am confident that ADHD is the most convincing and scientifically plausible hypothesis to explain Leonardo’s difficulty in finishing his works.
“Historical records show Leonardo spent excessive time planning projects but lacked perseverance. ADHD could explain aspects of Leonardo’s temperament and his strange mercurial genius.”
ADHD is a behavioural disorder characterised by continuous procrastination, the inability to complete tasks, mind-wandering and a restlessness of the body and mind.
While most commonly recognised in childhood, ADHD is increasingly being diagnosed among adults including university students and people with successful careers.
Leonardo’s difficulties with sticking to tasks were pervasive from childhood.
Accounts from biographers and contemporaries show da Vinci was constantly on the go, often jumping from task to task. Like many of those suffering with ADHD, he slept very little and worked continuously night and day by alternating rapid cycles of short naps and time awake.
Alongside reports of erratic behaviour and incomplete projects from fellow artists and patrons, including Pope Leone X, there is indirect evidence to suggest that Leonardo’s brain was organised differently compared to average.
He was left-handed and likely to be both dyslexic and have a dominance for language in the right-hand side of his brain, all of which are common among people with ADHD.
Perhaps the most distinctive and yet disruptive side of da Vinci’s mind was his voracious curiosity, which both propelled his creativity and also distracted him.
Catani suggests ADHD can have positive effects, for example, mind-wandering can fuel creativity and originality. However, while beneficial in the initial stages of the creative process, the same traits can be a hindrance when interest shifts to something else.
Catani, who specialises in treating neurodevelopmental conditions like autism and ADHD, says: “There is a prevailing misconception that ADHD is typical of misbehaving children with low intelligence, destined for a troubled life.
“On the contrary, most of the adults I see in my clinic report have been bright, intuitive children but develop symptoms of anxiety and depression later in life for having failed to achieve their potential.
“It is incredible that Leonardo considered himself as someone who had failed in life. I hope that the case of Leonardo shows that ADHD is not linked to low IQ or lack of creativity but rather the difficulty of capitalising on natural talents. I hope that Leonardo’s legacy can help us to change some of the stigma around ADHD.”
As for da Vinci’s horse, notebooks found in 1965 in Madrid included his sketches for the horse, which has resulted in several modern-day interpretations. His notes, perhaps not surprisingly, given Catani’s hypothesis, were far from systematic, and none pointed to the final position of the horse.
Interestingly, the first life-size version, created by a nonprofit organization in Pennsylvania, took more than 15 years, including sourcing finance for the $US2.5 million project.
Grey Matter Leonardo da Vinci: a genius driven to distraction
Marco Catani and Paolo Mazzarello
Brain, Volume 142, Issue 6, June 2019, Pages 1842–1846, https://doi.org/10.1093/brain/awz131