In 1602, Jacob van Heemskerck led a fleet of eight ships to the East Indies on a trading expedition. When he arrived, he learned about the Portuguese terror campaign to drive the Dutch from the spice trade and decided to punish the wrongs committed against his countrymen.

Heemskerck attacked the Portuguese carrack Santa Catarina (shown here at center in the only known contemporary depiction) on February 25, 1603 off the coast of Singapore. He seized the ship and hauled it to Amsterdam. where His employer auctioned its cargo for 3.5 million silver guilders.  To defend the seizure, the Dutch East India Company hired a young lawyer named "Hugo Grotius."

Hugo Grotius, depicted here at age 15, was a prodigy who so impressed the King of France with his erudition that Henry III dubbed him the “Miracle of Holland.” Here he holds the gold medal received from the French king.

Grotius, shown here at 16, worked as a lawyer but hated the job. “You know not, my worthy Hensius,” he wrote to his friend, “of how much time the ungrateful practice robs me.” Nevertheless the legal challenge of defending Heemskerck’s seizure fascinated him, and he spent more than two years writing a five-hundred-page treatise.

Grotius’ power in Dutch politics grew until he was convicted of heresy and sentenced to life imprisonment in 1618. He was imprisoned in Loevestein castle, accompanied by his wife and children. Grotius escaped after three years by hiding in a chest carried out of his cell by unsuspecting guards.

Though Grotius never published his defense of Heemskerck, it became the starting point for his greatest work, The Rights of War and Peace. In it, Grotius defended the view that war was a legitimate tool for enforcing legal rights.

Grotius has been celebrated in the centuries since his death as not only the “father of international law,” but also as a source of legal and moral guidance. He even appears in the U.S. House of Representatives Chamber, where his marble image is among 23 “Lawgivers” that circle the upper walls of the galleries, together with Moses, Hammurabi, and Thomas Jefferson.

From at least the fifteenth century, sovereigns who went to war published “manifestos” setting out their “just causes.” The first known war manifesto was written for Maximilian I, soon to be the Holy Roman Emperor. The first line reads: “No one does not know that the French are Roosters.”

Maxmillian I’s manifesto defended his resort to arms on the grounds that the French king, Charles VIII, stole his wife, Anne of Brittany (shown here praying). Her marriage to Maximillian I was annulled by the pope so she could marry the French King Charles VIII (the “rooster” from the first line of the previous manifesto). She continues to be celebrated in Brittany.

According to Grotius’s theory of “just war,” conquest and booty-taking were both perfectly legal  as long as the war was fought for a “just case.” In his series of drawings entitled “Miseries of War”, Jacques Callot attempted to convey the horrors of booty-taking.

In 1793, the French revolutionary government sent Edmond Charles Genet to convince the United States to support France in its war with Great Britain. A dashing man with polished manners and sparkling wit, he was also brash and outspoken. Even Thomas Jefferson, who was sympathetic to French cause, became impatient with his efforts to draw the United States into a European war.

To many of his enemies, Napoleon’s military prowess was unnatural. One popular etching from 1814 shows Napoleon swaddled and cradled in the loving arms of his father, Beelzebub. Nevertheless, even after Napoleon’s defeat at Leipzig and ouster from the throne, the Allies did not prosecute him for waging war—because waging war was perfectly legal. Instead, they sought to rid themselves of “the Devil’s Darling” by giving him the Island of Elba to rule as sovereign.

After his escape from Elba and subsequent defeat at the Battle of Waterloo, Napoleon surrendered on July 14, 1815. He was exiled yet again, this time to the remote South Atlantic island of Saint Helena, where he died in 1821.

Historians usually describe James Polk, the U.S. President who presided over the Mexican-American War in 1848, as an insatiable expansionist. But Polk claimed to have a “just cause” to go to war: Mexico had failed to pay its debts to the United States.

At the close of the U.S. war with Mexico, the United States seized much of what is now the American Southwest to settle the books.

Tasunka Ota (known as Plenty Horses) was put on trial in 1891 for killing Lieutenant Edward Casey in cold blood. He was acquitted when the judges determined that war existed between the U.S. and the Indian tribes, and he was therefore licensed to kill.

In 1853, Commodore Matthew Calbraith Perry led a U.S. expedition to Japan, which had been largely closed to trade with the West since the 1600s. Perry told Japanese officials who met his fleet that if the Japanese govenrnment did not deliver a letter to the Emperor offering a treaty of friendship, he and his men would deliver it “whatever the consequences may be.”

This woodblock print depicts the American steamship commanded by Perry as seen by the Japanese, most of whom had never before seen a ship that belched smoke and moved against the wind. The terrifying sight of Perry’s fleet sent “mothers flying with children in their arms and men with mothers on their backs.”

While waiting for his letter to be delivered, Perry directed several of his ships to survey the harbor and bay. The Japanese governor informed him that Japanese laws forbade such surveys, but Perry refused to back down. Armed only with swords to the American guns, the Japanese relented.

After the forceful opening of Japan by the U.S., the Japanese government sent a delegation of students to the Netherlands to learn about Western ideas. Nishi Amane, sitting at far right, and Tsuda Mamichi, behind him, were studying international law with Dutch scholar Simon Vissering when Vissering discovered the unpublished and long-forgotten defense of Heemskerck written by Hugo Grotius.

After he returned from the Netherlands, Nishi wrote Bankoku kōhō to introduce western international law to a Japanese audience. He modeled his text on Hugo Grotius’s masterwork, The Rights of War and Peace. The lower half of the 7th column on page 3 (shown here in the red box) is the katakana rendition of the name “Hugo de Groot” (Hugo Grotius).

Nishi became a leading scholar at the “Institute for the Study of Barbarian Books,” before joining the Meiji government. He devised nearly all of the most important Japanese army and navy regulations, wrote the rules of warfare carried by all Japanese soldiers, and served as private tutor to the then-teenaged Emperor, who would lead the country to its first wars in over two centuries.