The Astronomer Who Was Too Polite to Pee

On the evening of 13 October 1601, the Danish astronomer Tycho Brahe sat down to dinner at the residence of Peter Vok of Rožmberk, in the Old Town of Prague, and did not get up again until something inside him had ruptured.

He was fifty-four years old, in good health, and at the height of his European reputation. The Emperor Rudolf II had given him a castle outside the city and a salary larger than that of most of the imperial ministers. His assistant, a thirty-year-old German named Johannes Kepler, was waiting for him back at the observatory with the year’s reduced data. Tycho had spent the day reviewing star catalogues and was looking forward to the meal.

He died eleven days later. The cause, both in his own account and the standard biographical accounts that followed, was that he had needed to urinate during dinner, had been too polite to leave the table, and had held it for so long that his bladder had been permanently injured. He had then developed a urinary infection that killed him.

This is, very nearly, what happened. The exact mechanism has been debated for four centuries. In 2010, a team led by the Danish archaeologist Jens Vellev opened his tomb in the Church of Our Lady before Týn in Prague’s Old Town and tried to settle the question.

The man

Tyge Ottesen Brahe — Latinized to Tycho — was born in 1546 into the Danish high nobility and lost most of his nose at twenty in a duel with a Danish cousin over a mathematical disagreement. He spent the rest of his life wearing a prosthetic, made (according to most accounts) of brass alloyed with silver and gold, glued on with a wax-based adhesive. He kept several spare noses in a small leather case. The chemical analysis of the 2010 exhumation suggested that the prosthesis was actually mostly copper, brass-coloured, and rather plainer than tradition had it. The case has not been found.

He had built, on the Danish island of Hven, the most ambitious astronomical observatory ever constructed — Uraniborg, with its sister underground facility Stjerneborg — and had filled it for two decades with the most precise pre-telescopic measurements of the planets and stars that anyone had made or would ever make. His observations of the position of Mars, taken night after night for years, were the data from which Kepler would later extract the three laws of planetary motion.

He had quarreled with the new Danish king in 1597, packed up his instruments, and emigrated. The Emperor Rudolf, who collected scientists the way other monarchs collected paintings, had taken him in. Tycho had set up a new observatory in a castle at Benátky nad Jizerou, north of Prague, and then moved into the city itself in 1600.

He had hired Kepler in February 1600. The two men had quarreled for most of the year that followed, partly over salary and partly over whether Tycho was going to let Kepler look at the Mars data. By October 1601, the quarrels had subsided. Tycho was finally letting Kepler use the observations. They had work to do.

The banquet

The host on 13 October was Peter Vok of Rožmberk — the head of one of the wealthiest Bohemian noble families and a frequent host of imperial dignitaries. The meal was long. The guests drank, by Tycho’s own account in a letter dictated days later, “a great deal.” At some point during the meal Tycho realized he needed to urinate. He did not consider, in the etiquette of a noble Bohemian dinner, that he was free to interrupt the courses and leave the table.

He held it. The meal continued.

By the time he got home, he could no longer urinate. The condition is now recognized — acute urinary retention, sometimes triggered in older men by sudden bladder distension combined with alcohol and possibly an undiagnosed enlarged prostate. In 1601, with no catheters, no antibiotics, and no understanding of what was happening physiologically, the condition was a death sentence.

He went into a fever within forty-eight hours. He developed delirium. Kepler, who was at his bedside through most of the eleven days, recorded that he could pass small amounts of urine “only with the greatest pain.” A contemporary diary entry, possibly by Tycho’s personal physician Johannes Jessenius, describes him as “calling out, in his delirium, about his observations and instruments, fearing they would be scattered.”

He died on the morning of 24 October 1601. According to Kepler’s account, his last words, repeated several times, were Ne frustra vixisse videar: “Let me not appear to have lived in vain.”

The line is the most-quoted in the history of astronomy. Whether he actually said it is a question that hangs over Kepler’s account; Kepler had reason to want a tidy ending for the man whose data he was about to inherit. The line appears in his earliest letters about Tycho’s death, written within a week, and so if it is an embellishment it is an early one.

What was actually wrong

The bladder-rupture explanation came first from Pierre Gassendi’s biography of Tycho, written half a century later. Gassendi was working from Kepler’s notes, contemporary letters, and the standard early-modern medical assumption that a person who could not urinate had, by definition, a damaged bladder. The diagnosis stuck for almost three hundred years.

In the late nineteenth century, the Czech physician Vilém Heinrich proposed that Tycho had died of uremia — a buildup of toxic waste in the blood, secondary to acute kidney failure — and that the underlying cause was either an enlarged prostate or kidney stones. This explanation eventually became the medical consensus by the early 1900s.

Then in 1991, the Czech historian Jaroslava Folta noticed that traces of mercury had been reported in some of the hair samples taken when Tycho’s tomb was first opened in 1901. Mercury poisoning has symptoms that overlap with uremia in late stages. By the early 2000s, two possibilities were circulating: that Tycho had been poisoned by an enemy at the imperial court, or that he had poisoned himself with his own alchemical experiments. The favorite candidate for the human poisoner was Kepler, who, the conspiracy theory held, had wanted to inherit the Mars data and had been willing to kill for it.

This is the question Vellev’s 2010 exhumation was meant to resolve.

The answer in the bones

The exhumation took place in November 2010 in the presence of Czech and Danish scientists, the local archbishop, and television crews. The skeleton was photographed, sampled, and reburied within seventy-two hours.

The published results, in Archaeometry in 2012, were unambiguous. Mercury was present in Tycho’s hair, but at concentrations consistent with normal Renaissance exposure — anyone who handled alchemical equipment had measurable mercury. There was no spike in the hair samples corresponding to the eleven days of his final illness. He had not been poisoned, by himself or by anyone else.

The skeleton showed no signs of bladder stones, kidney stones, or skeletal changes consistent with chronic prostate trouble. The cause of death remained, in the team’s careful language, “consistent with uremia secondary to acute urinary retention” — exactly the diagnosis Heinrich had proposed in 1899, exactly the death Tycho himself had described in his last days.

He had really died, in other words, because he had needed to pee at dinner and had thought it would be rude to say so.

What followed

Kepler took possession of Tycho’s observation books within days, with the family’s permission and over the legal objections of Tycho’s son-in-law, Frans Tengnagel. He had the data of Mars in his rooms before the funeral. The first of his three laws of planetary motion was published in 1609; the second in the same volume; the third in 1619. Each of them was derived directly from Tycho’s tables.

Tycho is buried under a red marble slab in the Týn Church, on the south side of the Old Town Square in Prague, in a niche of the wall behind the right-hand pillar of the nave. The slab shows him in armor, with a sword, looking exactly like a man who had once fought a duel over an equation. The prosthetic nose is not depicted.

A small spare-nose case, possibly his, was reported in the inventory of his Prague rooms after his death. The inventory is preserved in the Czech state archives. The case is not.