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“Those 300,000 could not get past those 12,000.”

A line I heard in a strategic-thinking class

300,000 Against 12,000? The Siege of Vienna and the law of scarce resources

In the summer of 1683 the largest Ottoman army in decades stood before the walls of Vienna. Sixty days later it was beaten and gone. Why? The short answer: power is effective resources, not total resources. This page shows that step by step, and at several points asks you to make the call yourself.

Painting of the siege of Vienna: the walled city in the plain, the Ottoman camp and tents in front, and the wooded hills of the Kahlenberg on the left
Frans Geffels, painted within a decade of the siege. Look at the hills on the left: that is where the relief army came from.Image credit: Frans Geffels (1683–1694) · Public domain · Wikimedia Commons
days of siege, 14 July to 12 September
60
defenders: 11,000 soldiers and 5,000 armed citizens
16,000
men in the relief army that finished it
65–80k

Earn a medal in every interactive section. There are six on this page.

First, the numbers

300,000? No. And the 12,000 were not alone

For the analysis to hold, fix the numbers first. Flip the switch to see how the classroom version differs from what historians estimate today. Each figure is 5,000 men.

Ottoman army300k

The figure of the period's pamphlets; it counts labourers, crews and camp followers.

Defenders of Vienna12k
Relief army—

One figure = 5,000 men

So what did the 12,000 do?

They did not defeat the Ottomans. Their job was to last sixty days. The relief army won the decisive battle at the Kahlenberg. The good news is that the correction makes the strategic lesson stronger, not weaker: the defender did not need to win, only to buy time.

Three commanders

Three men, three different goals

Engraved portrait of Grand Vizier Kara Mustafa Pasha in a turban
Kara Mustafa Pasha, Grand Vizier.Image credit: Rijksmuseum, RP-P-1894-A-18289 · CC0 · Wikimedia Commons

Kara Mustafa Pasha

Ottoman Grand Vizier, commanding the siege

Goal: take the city, intact and rich, before autumn.

100,000–150,000 men, mostly light guns

Engraved oval portrait of Count Ernst Rüdiger von Starhemberg in a long wig
Ernst Rüdiger von Starhemberg, commander of the city.Image credit: Engraving by J. le Pautre · Public domain · Wikimedia Commons

Ernst Rüdiger von Starhemberg

Commander of the Vienna garrison

Goal: just hold out until relief arrives.

11,000 soldiers, 5,000 citizens, 300+ guns

Painted portrait of King John III Sobieski in armour and a leopard skin
John III Sobieski, King of Poland, who led the relief.Image credit: Attributed to Jan Tricius, c. 1680 · Public domain · Wikimedia Commons

John III Sobieski

King of Poland, commanding the relief

Goal: come down from the heights and break the camp.

65,000–80,000 Polish and Imperial troops

Effective resources

A big army is also a big consumer

The principle of scarce resources says every resource is limited and every choice costs you another option. The common mistake is to think a bigger army means more resources. Kara Mustafa was short of exactly the resources that decided the outcome.

Time

The army arrived on 14 July. The campaigning season was short and the army had to be home before winter.

Heavy siege guns

Left behind to move faster. About 110–150 guns, almost all light.

Supplies

Feeding more than 100,000 people on enemy ground cost more every day.

The commander's attention

Split between the siege, raiding the countryside and the relief army's threat.

A stone cannonball set into a niche on a building facade in Vienna's Sterngasse, with a plaque below
A "Turkish ball" still set into a wall in Vienna's Sterngasse. The Ottomans brought mostly light guns: they could hurt the city but not open it quickly.Image credit: Stefan Ivanovich · CC0 · Wikimedia Commons

Every day of delay cost the attacker far more than the defender.

The siege clock

Sixty days, one hourglass

Drag the slider. Every day that passes is a small win for the defender and a large cost for the attacker.

Day 6012 September 1683
Defender's goal
Days bought: 60 / 60
Attacker's cost
Supplies, disease, a season running out
12 September 1683

The Battle of the Kahlenberg

In the afternoon the cavalry comes down from the hills and the Ottoman camp breaks.

The war council

You are Kara Mustafa

Five decisions he actually made. Make each one yourself and see what it costs you. Then see what history did.

You are the Grand Vizier. Your army is before Vienna, and you know a relief army is coming.

Focus on the scarce resource

Decision 1 of 5

Bring the heavy siege guns, or travel light?

Why they held

Scarcity forced the defenders to focus

Five reasons a small garrison held for sixty days against an army several times its size. Tap each one.

A simple goal

The defender did not have to win, only to buy time. The attacker had to win. That asymmetry of goals changes everything.

The interior-lines race

Defenders from the centre Attackers around the ring
A hand-drawn Ottoman plan of the 1683 siege: the walled city at the centre, ringed by trenches and coloured tents
The siege as the Ottomans drew it (Wien Museum). The camp rings the city on a long outer line; the defenders hold a short inner one.Image credit: Wolfgang Sauber (resized) · CC BY-SA 4.0 · Wikimedia Commons
Józef Brandt's panoramic painting of the Battle of Vienna: cavalry clashing in smoke under a wide sky
Józef Brandt, Battle of Vienna (1863). The charge came in the late afternoon of 12 September.Józef Brandt (1863) · Public domain · Wikimedia Commons

12 September

The charge from the Kahlenberg

Scroll down and follow the charge.

View from the Kahlenberg over Vienna and the Danube in the distance
The view from the Kahlenberg today. Whoever holds these heights sees the whole plain, and the Ottomans never fortified them.Image credit: Sharon Hahn Darlin (resized) · CC BY 2.0 · Wikimedia Commons
Wojciech Kossak's painting of Polish hussars riding past King Sobieski, with the Kahlenberg church on the hill behind
Wojciech Kossak (1924). The church on the hill is the Kahlenberg.Image credit: Wojciech Kossak, National Museum in Kraków · Public domain · Wikimedia Commons
A Polish winged hussar's armour and wings on a model horse in a museum
Winged hussar armour. About 3,000 hussars rode at the centre of the charge.Image credit: Thomas Quine (resized) · CC BY 2.0 · Wikimedia Commons
KahlenbergDanubeViennaOttoman camp
  1. MorningThe relief army comes down from the heights of the Vienna Woods. On the left, Imperial troops under Charles of Lorraine engage first.
  2. MiddayThe Ottomans are caught between two fires: behind them a city that has not fallen, in front of them an army coming from above.
  3. AfternoonAbout 18,000–20,000 horsemen, with some 3,000 Polish winged hussars at the centre, ride down from the hills.
  4. EveningThe Ottoman camp breaks. The Grand Vizier's tent falls to the attackers and the siege is over.
  5. It is often called one of the largest cavalry charges in history. "The largest" is a popular claim that cannot be proven.

It is often called one of the largest cavalry charges in history. "The largest" is a popular claim that cannot be proven.

A critical view

Four stories to tell with care

Flip each card to see what historians say.

The business transfer

This is the startup-versus-incumbent story

The big company has money and people, but its focus is spread across ten goals. The small startup has one goal, one market, one advantage.

Kara Mustafa / the incumbentStarhemberg / the startup
Many resources, scattered focusFew resources, one goal
Wants everything at onceKnows the one thing that must survive
Underestimates the second threatKnows from day one when the relief arrives
Every day of delay costs moreEvery day held is a win

The mirror

Are you Starhemberg or Kara Mustafa?

Four questions about your own working week. The answers stay in your browser.

Do you have one written goal for this quarter?
Do you know where your rival's "relief army" will come from?

Kara Mustafa

Your resources (time, money, attention) are spread across many projects. By this principle you probably reach the decisive point in none of them.

A simple test: if less than half of your weekly hours go to one main project, it is worth a second thought.

Nothing is stored or sent.

In one sentence

“Victory does not go to whoever has more resources; it goes to whoever concentrates scarce resources at the decisive point, at the right time.”

Abundance made Kara Mustafa careless. Scarcity made the defenders precise.

Method and sources

How this report was made

  • The analysis began with a line I heard in a strategic-thinking class. Before publishing, every number and date was checked against historical sources and several famous figures were corrected, above all the 300,000.
  • Forces are given as ranges because historians give ranges. Casualties are estimates too: the garrison lost some 4,000–5,000 soldiers, and the Ottomans about 8,000–15,000 killed and wounded on the day of the battle.
  • The war-council game scores this lesson; it does not predict an alternative history.
  • Medals are stored in your own browser, and the mirror's answers are not stored anywhere.

Sources

  1. John Stoye, The Siege of Vienna (1964; rev. Birlinn 2000)
  2. Andrew Wheatcroft, The Enemy at the Gate: Habsburgs, Ottomans and the Battle for Europe (2008)
  3. Encyclopaedia Britannica, Siege of Vienna (1683)
  4. Encyclopaedia Britannica, Treaty of Karlowitz
  5. John J. Mearsheimer, Assessing the Conventional Balance: The 3:1 Rule and Its Critics, International Security 13(4), 1989
  6. Austria-Forum, Kaffeehaus (Johannes Diodato, 1685)
  7. Baki Tezcan, The Second Ottoman Empire (Cambridge University Press, 2010)
300,000 Against 12,000? | Farjad