To obtain an accurate assessment of conditions in Cuba, Madden developed the habit of showing up on plantations unannounced, providing him an opportunity to see beyond the colonial façade of lavish hospitality to invited guests and to refute the so-called ‘benign treatment’ of slaves in Spanish colonies. What he observed remained etched in his memory, as his anguished testimony made clear: ‘So transcendent the evils I witnessed, over all I had ever heard or seen of the rigors of slavery elsewhere, that at first I could hardly believe the evidence of my senses’ (Madden 1891: 77). Some of the more egregious practices he documented were the twenty-hour work day at harvest time and the appalling conditions of the ingenios, or sugar mills, which he described as ‘hells on earth’. Withstanding pressure to turn a blind eye to abuse, he gained powerful enemies and found himself in a life-threatening situation on at least one occasion. Regardless of the obstacles, the valiant doctor remained fiercely independent, prompting one unscrupulous slave-keeping British official appointee in Havana to declare that he agreed with Lord Sligo’s assertion that ‘he [Madden] wouldn’t agree with an angel from heaven’ (Ó Broin 1971: 95). 

No episode portrays the nature of the conflict in Cuba more clearly than that surrounding the British vessel Romney. Shortly after his arrival in Cuba, instead of seeing to the break-up of the captured slave ships as stipulated by the 1835 Anglo-Spanish treaty, Madden proposed that these ships be used to accommodate Africans liberated by the Mixed Anglo-Spanish Court until they could be transported to safe locations. Once the Africans were liberated, it was Madden’s responsibility to arrange for their safe passage to neighbouring islands - a sizeable task, given the concerted opposition of powerful interests.

Later, he convinced his employer of the need to procure the Romney, a superannuated warship, as a permanent hospital ship to provide accommodation and medical assistance to the men, women, and children rescued from the slave ships. The infuriated Tacón refused to allow the Romney’s crew of free and newly liberated Africans to come ashore, so the vessel remained at anchor in the harbour at Havana. Drawing on his medical expertise, Madden maintained the vessel as a hospital ship whose presence became an affront to the slave-holding oligarchy. Defiantly, the Romney remained anchored in the bay at Havana for almost nine years, long after Madden’s departure, as un baluarte del abolicionismo en el corazón del esclavismo (‘a bulwark of abolition in the heart of slavery’) (Ortiz 1975: 23).

As he was preparing to leave Cuba for London, Madden read an article in The Sun newspaper about an incident involving a number of enslaved Africans on board a Cuban schooner, the slave ship Amistad. Under the headline, ‘The Long, Low, Black Schooner’, the article, which included a sketch of the six-year-old, 170-ton vessel ‘of Baltimore clipper build’, reported the arrest and detention of the Africans. On his own initiative, and without prior approval from his employer, Madden immediately sailed for the United States to give key evidence in the case of the captives of the Amistad.

In one of the most famous trials of the age, fifty-two Africans were charged with mutiny and murder on board the Amistad as they struggled to overcome and escape their captors. An expert witness with first-hand knowledge of the operation of the Cuban barracones, or slave barracks, Madden visited the Africans in the New Haven County Jail, where he addressed the captives in Arabic. Since he had procured the emancipation of hundreds of Africans and had visited the Misericordia slave barracks in Havana just a few weeks previously on 24 September 1839, he could testify with authority as to the status of those held. The captives had been purchased from Don Pedro Martínez, of Martínez and Company - ‘a notorious house’ - one of the largest slave traders in Havana, with slave forts along the coast of Sierra Leone.

The prosecuting attorneys argued that the captives were ladinos, the term used on the transportation licence, and had been brought to Cuba before 1820, the year in which the slave trade became illegal. They made the case that, because the accused were slaves before the law changed, they were therefore legally held property. Although translated by US officials as meaning ‘able-bodied’, Madden clarified that, in Cuba, the term ladino was specifically used to denote Africans enslaved before 1820. In his deposition, dated 20 November 1839, he testified that the accused were ‘bona fide bozal negroes quite newly imported from Africa’, or Africans recently kidnapped and transported to Cuba to be sold into slavery, in contravention of the law. His evidence showed that their return to Cuba, as desired by President Van Buren, meant instant death at the hands of interests aligned with the ruling saccharocracy determined to make an example of the captives for would-be insurrectionists (Jones 1987: 109).

Madden’s deposition proved that the captives, some of whom were less than 19 years old at the time of the trial, were indeed bozales and were therefore illegally held. Much later, summarising the arguments for the accused, former US President John Quincy Adams stated that this distinction was one of the most important points of the case. [7] The fearless doctor also drew attention to Cuba’s blatant disdain for Spain’s international anti-slavery treaties exemplified by the imposition of a $10 ‘voluntary contribution’, or tax levied on each slave introduced to the island, the proceeds of which flowed into the Captain-General’s coffers.

The Amistad affair aroused international interest, threatening to interfere with relations among the major powers, the US, Spain, and England, over jurisdiction. Madden’s role in the case helped strengthen ties between the British and Foreign Anti-Slavery Society and American groups opposed to the ‘odious institution’. Although the Irishman travelled to the United States and gave evidence at his own expense and without prior approval from London, his employer at the Colonial Office, Lord John Russell, later to become Prime Minister, recognising the significance of Madden’s actions, subsequently commended him for his actions in defence of the Amistad captives (Madden 1891).