German military leader and strategist Karl von Clausewitz (1780-1831) has been called the "father of modern warfare." As a member of the officers' corps of the mighty Prussian army from an early age, Clausewitz witnessed some of the most decisive European battles of his century and culled his observations into a body of theories that were outlined in his 1832 tract, On War. Its most enduring statement, "War is a continuation of policy by other means," has been widely misconstrued.

Clausewitz was born Karl Philipp Gottlieb von Clausewitz on June 1, 1780 in the Prussian city of Burg, near Magdeburg, capital of Saxony-Anhalt. He was one of six children of Friedrich Gabriel von Clausewitz, a retired Prussian army officer. Though Prussia no longer exists as a sovereign nation, during Clausewitz's lifetime it was one of Europe's most formidable powers. It originated as a duchy in the seventeenth century, and eventually acquired enough territory and influence to crown a king. Prussia remained independent from the Holy Roman Empire, but enjoyed close ties to it. The military campaigns led by the armies of Frederick the Great greatly added to its territory.

Clausewitz's formal military training began at the age of twelve, when his father brought him to the headquarters of the 34th Infantry Regiment in Potsdam in 1792. Here he began his training as an officer cadet. Such early martial instruction was not uncommon in the Prussia of the late eighteenth century. His older brother, Wilhelm, was already a second lieutenant with the corps. Not long after his arrival at the barracks, Clausewitz witnessed his first battle, when his regiment was sent to liberate the cathedral city of Mainz from French occupying forces. Clausewitz's duties as a Fahnenjunker, or ensign, apart from carrying the regimental standard in marches, included visiting the wounded in the field hospitals and writing reports on them to his commanding officer.

At the King's Court

When the Prussian army withdrew from participation in the French Revolutionary Wars in 1795, Clausewitz was posted to a remote garrison for several years. He occupied his time by reading a great deal, and studying for the entrance examination to the Institute for Young Officers in Berlin. In 1801, he took the test and was accepted. Its director, Gerhard von Scharnhorst, would become a key figure in the modernization of the Prussian army. He implemented changes that would make it one of the most successful forces of the coming century.

Scharnhorst recognized Clausewitz's abilities and became the young officer's mentor. In 1803, Clausewitz graduated first in his class from the Institute, and was appointed military adjutant to the young Prussian prince, August. With this prime posting, he entered the rarefied world of the Berlin royal court, with its round of balls, banquets, and lavish official ceremonies. It was an enriching, but difficult time for Clausewitz. He was still a low-ranking officer with a correspondingly paltry pay rank. Many of his fellow officers were of noble birth and possessed independent family incomes. Still, Clausewitz became acquainted with many famous European political and cultural luminaries of the day here, and also met his future wife at a Berlin gathering late in 1803. Countess Marie von Bruhl came from an old, esteemed Saxon line of aristocrats. It took several years of engagement before her family would grant approval for her marriage to Clausewitz.

Prisoner of War

In France, Napoleon Bonaparte had exploited the political and economic chaos of the post-revolutionary years and seized power. He proclaimed himself emperor in 1804, and launched a war that added territory to France despite opposition from a coalition of British, Austrian, Russian, and Swedish forces. Prussia joined the fight in 1806, but suffered devastating losses at Jena and Auerstadt. It would mark a turning point for both Clausewitz and Prussia. He and Prince August were captured in the area near Prenslau and taken as prisoners of war.

Clausewitz's captivity was not a punitive one. Officers who were taken into custody by a foreign power were usually allowed to move about freely; they only had to surrender their insignia and weapons, and swear an oath that they would not take up arms against the detaining army. Thus Clausewitz spent part of 1806 in Berlin and Neu-Ruppin, but was then sent with Prince August to Soissons, France, where he spent half of 1807. He began writing articles about the military debacles of the previous year. "Observations on Prussia in its Great Catastrophe" was finished in 1806. Its criticisms of how the Prussian regiments had lost at Jena and Auerstadt were considered so inflammatory that the work would not be published in Germany for another seven decades.

Sided with Russia

A major political capitulation occurred in 1807, when Prussian king Friedrich Wilhelm signed an agreement with Napoleon. The treaty handed over nearly half of Prussian land to the French. This was seen as a humiliating defeat and incensed many officers, including Clausewitz. Still, it meant that he and the prince were released from official detention. Clausewitz returned to Berlin to aid Scharnhorst, who had been named head of the newly created Prussian Ministry of War and was working to reorganize and reform the army. In 1810, Clausewitz was promoted to the rank of major and began teaching at Berlin's Kriegsschule, the newly reconstituted school from which he had himself graduated with top honors. His salary and good repute combined to finally win the approval of the von Bruhl family. He and the Countess were married at St. Mary's Church in Berlin on December 17, 1810.

Tension between Prussia and Napoleonic France became strained. In February 1812, King Friedrich Wilhelm approved a request to send a Prussian corps of 20,000 men to join Napoleon's march on Russia. Clausewitz wrote a severe denunciation of this act of treachery that went unpublished for several years. Then he resigned, (as did many other high-ranking officers), and took up arms on the Russian side. Before his departure, he left with Crown Prince Friedrich Wilhelm--for whom he served as military tutor--a manuscript for safekeeping. This work, containing many of his theories and tactics, was the forerunner of his later treatise, On War.

Victory at a Terrible Price

In Russia, Clausewitz participated in several infamous battles. The French army managed to reach Moscow, but was decimated by its long, harsh winter. In late November 1812, a turning point was reached when the French were routed at the Berezina River. In the last days of the calendar year, Clausewitz was involved in negotiations that came to be known as the Convention of Tauroggen. This changed the course of the war decisively. The entire Prussian army joined with the Russians to defeat the French, and won a great victory at Leipzig in October 1813. Paris was seized five months later, and Napoleon was banished to the Mediterranean island of Elba.

After Tauroggen, Clausewitz was reinstated in the Prussian army as a colonel. However, he still was disliked by King Friedrich Wilhelm, and was not appointed to any command position. In early 1815, Napoleon escaped from Elba and once again gathered a force that retook Paris and did battle with a combined force of Prussian, Austrian, British, and Russian troops. At the battle of Ligny, at which Clausewitz was present, the French inflicted great casualties. Napoleon was defeated that same week by the British at Waterloo, in Belgium.

A Low Profile

In October 1815, Clausewitz was appointed chief of staff for Prussia's Army of the Rhine. He and his wife lived in Koblenz, Germany at this time. In 1818, Clausewitz was promoted to the rank of general and became the administrative director of the Kriegsschule. He had been recommended for the post by another key figure in the Prussian military organization, August von Gneisenau. Clausewitz had come to known Gneisenau through Scharnhorst, and had served under him during the Napoleonic Wars.

The position was a rather dull one, however, and Clausewitz spent much of the 1820s writing his opus. Because of the continued disfavor of the king and a postwar mood of conservatism, he was not able to teach or implement any of his ideas at the officers' college. He kept a low profile, and was even known as somewhat of a recluse. There were rumors that he was a drinker, due to his ruddy complexion. But this was caused by dermatological damage he had suffered during the Russian winter of 1812, when battlefield temperatures sometimes dropped to forty degrees below zero.

In 1830, tensions erupted at Prussia's border with Poland. Clausewitz had harsh words for the Poles, whom he considered unfit for self-government. He was appointed chief of staff to Gneisenau, commander of Prussia's Army of the East, and departed for Breslau, to serve as an inspector near the border. Before he departed, he sealed all his manuscripts, including what would become On War.

War was averted, but a cholera epidemic struck the area in late 1831, and felled Gneisenau in Poznan. Clausewitz was quarantined for a time, but then allowed to return to Breslau. Ten days later, on November 16, 1831, he died of cholera. His wife edited the manuscripts and had them published in 1832.

Theories of Conflict

On War, the work's English title, is difficult reading in any language. Its eight sections bear headings such as "On the Nature of War," "The Engagement," "Defense," and "War Plans." Clausewitz believed that the time-tested mathematical strategies for battle were increasingly useless in his modern age. War, unlike mathematics, was mostly unpredictable. In his writing, Clausewitz draws upon his own battlefield experiences in detailing innovative methods of retreat, flank positions, marches, and subsistence. He also wrote at length on more theoretical topics, such as his notion of what he called "absolute war." This would become On War's most infamous and misunderstood passage. According to Clausewitz, absolute war was violence unchecked by any controls, whose aim is to utterly annihilate the enemy. "The destruction of the enemy's military force is the leading principle of war; ...The results will be greatest when combats unite themselves into one great battle," he wrote. But Clausewitz went on to note that in reality, such abstract "pure" war did not exist, for political strategies and goals served to restrain such massive carnage.

On War belongs to a genre of controversial works that have, at times, been subject to many conflicting interpretations--Machiavelli's The Prince and Das Kapital by Karl Marx have earned a similar place on the bookshelves of history. Indeed, the Marxist-Leninist theory of war is culled significantly from Clausewitz's theories. It remains an important, though controversial text in military academics, and has been an integral part of the United States officers' curriculum since the aftermath of the Vietnam War.

Clausewitz's groundbreaking writings have prompted some to note wryly that as people became more civilized, warfare grows increasingly vicious. Despite the nature of his professional beliefs, Clausewitz was anything but a belligerent man. Extant images and memoirs reveal him as serious, shy, and, in appearance, closer to that of a poet or composer than the stereotypical Prussian general.

Further Reading

• Aron, Raymond, Clausewitz: Philosopher of War, Simon and Schuster, 1983.
• Parkinson, Roger, Clausewitz: A Biography, Stein and Day, 1971.