VLADIMIR PUTIN has not been verifiably seen in public since March 5th, and no one knows why. The Russian president has postponed a planned visit on March 11th to Kazakhstan. Moscow is abuzz with rumours linking the president's sudden reticence to the murder of Boris Nemtsov. Some hint that tension between Mr Putin and his Chechen surrogate, Ramzan Kadyrov, over the arrest of five Chechen men accused of killing Mr Nemtsov is to blame. Other rumours have been more outlandish. Andre Illarionov, a former advisor of Mr Putin's, wrote in a blog post that a coup might be underway; a Swiss tabloid reported that Mr Putin had flown to Switzerland to attend the birth of a love child with a Russian gymnast. Russia's government says Mr Putin has simply been feeling a bit unwell.

What is one to make of it all? In the absence of better information, one might ask what it has meant in the past when rulers of secretive governments vanished from public view. Of course, analogising current Russian politics to a distant and vastly different past can easily mislead. But in situations like this such comparisons can be educational, and they are certainly lots of fun.

Take the year 1564, a rather bad one for Tsar Ivan IV (also known as the "Formidable" or "Terrible") and many of his more powerful subjects. The tsar's wife Alexandra had died several years earlier after a wasting illness. The tsar believed someone in the Kremlin had poisoned her. Disputes and suspicions of disloyalty among the boyars (as the senior nobility were known) led Ivan to engage in increasingly strict repression, including the execution of Daniil Adashev, a hero of Russia's 1559 military campaign in Crimea, along with his family.

After Adashev's execution, prince Andrei Kurbskiy, formerly a favourite general of Ivan's, defected to the West. From the safety of Lithuania, Kurbskiy sent Ivan a famous series of letters denouncing his oppression of the nobles and generals who had so patriotically conquered new territories for him. Ivan himself was a better stylist than Kurbskiy, and sent back lengthy, brutally witty replies that were distributed to a broad audience—perhaps the earliest examples of a Russian regime engaging in ideological propaganda. Ivan is generally seen as pioneering the combination of high ideological appeal and vulgar populist insults which so many Russian leaders have since deployed. Among other things, Ivan asks: "If you are as just and pious as you say, why did you fear a guiltless death, which is no death but gain?" In other words, if you're so righteous, why didn't you stay here and let me kill you? He compares Kurbskiy unfavourably to the latter's emissary Vaska Shibanov, who, he says, had the bravery to continue praising his master even as Ivan had him tortured to death.

Ivan faced challenges within and without. He had turned his attention from Crimea to invading the Baltics, but with Kurbskiy now fighting for the Lithuanians, the situation was developing not necessarily to his advantage. The boyars were increasingly nervous that defeats abroad would lead to accusations of treason at home. On December 3rd Ivan left Moscow with an unusually large retinue on what was presented as a routine pilgrimage to one of the monasteries that surround Moscow. Some historians describe Ivan's departure as "secret"; in any case, he made no arrangements for who would rule in his absence.

And then, for a month, nothing was heard from the tsar.

Ivan, it turned out, had settled into residence in the fortress town of Alexandra Sloboda, west of Moscow. A month after the tsar's disappearance, two letters from him were read out by church prelates in Moscow. The first announced his intention to abdicate. He blamed the boyars' disloyalty and squabbling for his decision. The second addressed the people of Moscow, whom he praised for their Christian loyalty in the face of the boyars' impiety.

Unable to rule in Ivan's absence or to settle internal disputes, the boyars grew afraid that the state might disintegrate. Ivan's sudden departure had demonstrated Russia's complete dependence on his person. There were no plausible alternative rulers. The boyars sent Ivan a delegation requesting that he return to the throne. Ivan agreed, on the condition that he be allowed to arrest anyone on suspicion of treason, regardless of rank.

On returning to Moscow in 1565, Ivan established a new institution known as the oprichnina, effectively a type of secret police under his direct control. The ranks of the oprichnina were largely filled with lower gentry who swore personal loyalty to the tsar. For the next seven years, the oprichnina subjected Russia to a reign of terror, arresting and executing boyars for treason and confiscating their estates, which were promptly awarded to the oprichniki themselves. After some time, inevitably, the oprichniki began targeting each other for denunciation and execution, and in 1572 Ivan dissolved the increasingly chaotic organisation.

In the meantime the independent authority and privilege of the boyar class had been smashed. The tsar's sudden disappearance from Moscow at the end of 1564 had forced the aristocracy to acknowledge its weakness, and to give him free rein to reform as he saw fit. Ivan's state-building exercise had taken Russia another step towards solidifying the centralised, autocratic monarchy that would rule until 1917.

What does this have to do with Mr Putin's sudden absence? Probably nothing. Perhaps Mr Putin really has been sick. He is scheduled to meet with Almazbek Atamaev, president of Kyrgyzstan, in St Petersburg on Monday, which may dispel the rumours. In the meantime it is useful to recall that when an autocrat disappears, it is not always a sign of weakness. As many analysts point out, Mr Putin's vanishing act has Russians as keenly aware as ever of the government's dependence upon him. Mr Putin, if healthy and unbothered, will not mind the reminder.