John Bankhead Magruder (May 1, 1807 – February 18, 1871) often referred to as "Prince John Magruder", was an American and Confederate military officer. A graduate of West Point, Magruder served with distinction during the Mexican–American War (1846–1848) and was a prominent Confederate Army general during the American Civil War (1861–1865). As a major general, he received recognition for delaying the advance of Maj. Gen. George B. McClellan's Army of the Potomac, during the 1862 Peninsula Campaign, as well as recapturing Galveston, Texas the following year.

When the Civil War began in 1861, Magruder left the Union Army to accept a commission in the Confederacy. As commander of the Army of the Peninsula, he fortified the Virginia Peninsula and won the Battle of Big Bethel. In the Peninsula Campaign, he stalled McClellan's Army of the Potomac outside Yorktown, allowing Maj. Gen. Joseph E. Johnston to arrive with reinforcements, organize a retreat, and defend the Confederate capital, Richmond. Magruder was criticized for his leadership in battles at Savage's Station and Malvern Hill during the Seven Days Battles. He spent the remainder of the war administering the District of Texas, New Mexico, and Arizona and the Department of Arkansas; in his tenure, Magruder lifted the naval blockade over Galveston and recaptured the city in 1863.

After surrendering the Trans-Mississippi Department in June 1865, Magruder fled to Mexico. He worked in an administrative role under Emperor Maximillian I before returning to the United States in 1867. In 1869, he embarked on a lecture tour, speaking on the Mexican monarchy. Magruder died in Houston in 1871.

Early life and career John Bankhead Magruder was born in Port Royal, Virginia, on May 1, 1807. He was the fifth child of ten, eight of whom lived past infancy. Magruder's father Thomas was from a family of Scottish plantation owners; on June 22, 1797, he married Elizabeth Bankhead, the eldest daughter of "noted millers" in Albemarle County. Thomas Magruder was an attorney and practiced in the Chancery Court of Fredericksburg, but he was negligent in his duties and a constant debtor. By 1820, he lost ownership of all his slaves, and his homestead was sold at public auction five years later. Thomas was eventually reduced to living on Elizabeth's property in Aberfoyle with his daughter Isabella, while his wife lived with their son Allan in Albemarle County.

John Magruder was not interested in the law but loved the idea of soldiering. His uncle James Bankhead, a military officer during the War of 1812, is assumed to have instilled in Magruder a fascination with combat, in large part because of the war stories that he and Colonel James Bankhead – Magruder's American Revolutionary War veteran grandfather – told. In 1825, on letters of recommendation from his father, uncle, and Virginian congressman Robert S. Garnett, Magruder was notified of his appointment to West Point where he was to report a year later. He spent one semester at the University of Virginia in the interim.

At West Point, Magruder was a hyperactive and ambitious cadet who was often at odds with superintendent Sylvanus Thayer's regulations. His closest friends were William N. Pendleton and Alexander J. Swift; the former was later a Confederate officer and the latter distinguished himself as top of Magruder's class. He graduated in 1830, fifteenth in his class of 42 cadets, and was commissioned as a brevet second lieutenant in the 7th Infantry Regiment.

Magruder spent most of his furlough in the company of 20 year-old Henrietta von Kapff (March 27, 1810 – January 1, 1884), the wealthy daughter of businessman Johann von Kapff. The couple soon began a romance and married on May 18, 1831. They had three children; Isabella (1833 – July 20, 1869); Katherine Elizabeth (1836 – April 26, 1896); and Henry R. (1841 – January 31, 1907).

His family occasionally traveled with Magruder during his various assignments but, because of the unfavorable conditions in the various remote locales, Henrietta found it more practical to live in Baltimore where she could raise their children and stay close to her business interests. Thereafter, Magruder infrequently spent time with his family; he last saw them as he tended to Isabella during an illness that led to her death in 1869. Despite his absences, close family friends noted that Henrietta remained "in love with [her husband] to an uncommon degree".

U.S. Army career On a request to the United States Department of War, Magruder arranged a transfer to the 1st Artillery with Albert Miller Lea, a correspondent from West Point, to stay close to Henrietta. Biographer Thomas M. Settles described the lieutenant as a great favorite among his men—‌"always charming, frivolous at times, but intelligent and obviously well read". Known as "Prince John", a resplendently uniformed man with a theatrical manner, Magruder attained a reputation for his social grace and etiquette.

The 1830s for Magruder, however, were largely regulated to garrison duty in North Carolina, Maryland, and Florida; the uneventful aspects of these assignments granted him time to study law and pass the bar examination. By 1844, Magruder, working as a recruitment officer, was dissatisfied with military service. The adverse northern climate found at his latest post, the Hancock Barracks in Maine, contributed to a bronchial infection, he had seen no military action, and felt slighted by the lack of recognition for organizing crucial supplies during the Second Seminole War.

In August 1845, Magruder volunteered for assignment in Corpus Christi, Texas, to join General Zachary Taylor's army there, occupying the former republic; the US was on the verge of war with Mexico over the question of annexation. After hostilities opened on April 25, 1846, Magruder first saw combat at the Battle of Palo Alto, 14 days later. On April 18, 1847, Magruder served with "zeal and ability", in General Winfield Scott's expedition, under heavy fire and turned Mexican artillery against them at Cerro Gordo, for which he was praised by his superiors and brevetted to major.

By September 12, US forces had begun targeting Chapultepec, in one of a series of engagements in the Battle of Mexico City. Magruder—lightly wounded—ordered the first shots in the early morning on the 13th and offered pursuit, despite superior Mexican numbers, to capture the Anzures, Veronica, and Belen intersection—a crucial crossroads that would block efforts by General Santa Anna to relieve the palace.

From the conflict in Mexico, Magruder learned the value of deceiving and flanking forces outnumbering his own. He also saw the war as demonstrating "the science of artillery is continually advancing", and submitted a detailed plan for separating the light artillery from "ordnance, field, and sea coast artillery"—in theory, "resulting in an enlightened division of labor" and specialization; however, in a post-war cost-cutting decision, the War Department rejected the proposal and ordered Magruder's men to serve as foot soldiers.

In 1850, Magruder was assigned to command the post in San Diego, California, where for a time he was also "a land speculator, lawyer, saloon owner, railroad president, and one of California's most celebrated duelists". In the late 1850s Magruder took Rancho Jamacha from Apolinaria Lorenzana. Years later in May 1857, while stationed at Fort Adams, his company was remounted as a light artillery battery. Historian Edward A. Pollard noted that Magruder was recognized as one of the lead artillerists in the army: "It was in the rapid and effective management of field-pieces, and the combinations with which they were applied to accomplish immediate and important results, that his genius shone"; Magruder's experience helped him convince the War Department in 1860 to accept a revised version of his logistics plan, and fund an expedition to observe European artillery tactics.

Civil War At the onset of the Civil War Magruder was posted in Washington, D.C. on the side of the Union. However, Magruder, whose loyalties were with his home state of Virginia, resigned his commission in the army four days after the state seceded on April 17, 1861, to join the Confederate States of America (CSA); subsequently, Governor John Letcher appointed him to colonel in the Confederate Army. His superiors—perhaps impressed by his detailed inventory of Richmond's defenses—placed Magruder in command of forces, soon officially termed the Army of the Peninsula, on the Virginia Peninsula, east of Richmond where the city seemed most vulnerable to Union attack.

Immediately after establishing his headquarters at Yorktown, Magruder surveyed the region and found the circumstances favorable: the marshy terrain, dense undergrowth, and watercourses led him to surmise that a successful defense of the Peninsula was plausible. He ordered the construction of three fortified lines to counter mounting Union forces under the command of Maj. Gen. Benjamin Franklin Butler at Fort Monroe.

On May 27, Butler sent a force 8 miles (13 km) north to occupy the lightly defended town of Newport News and expanded Camp Hamilton, established in the adjacent town of Hampton. Magruder, seeking to delay his opponent while awaiting men and supplies, prepared a well-defended advanced outpost at Big and Little Bethel just 8 miles (13 km) from Union camp at Newport News to goad Butler into a premature attack; Butler complied and suffered a defeat in the Battle of Big Bethel on June 10. Civilian intelligence reports and a friendly fire incident during the night exposed the position of Butler's troops whose initial advance and subsequent thrusts were thwarted despite a Confederate disadvantage of manpower.

The praise for Magruder following Big Bethel far superseded its tactical importance but it nonetheless had a profound psychological impact. His victory reaffirmed the belief of many southerners in the Confederate cause, and Civil War historian Douglas Southall Freeman wrote Magruder was one of its earliest heroes—"second only to Beauregard in the esteem of the Confederacy" prior to the Seven Days Battles. By August 1861, he rose to the rank of major general.

Peninsula Campaign Defending the peninsula

The victory of the Confederates at the First Battle of Bull Run on July 21, 1861, had paralyzed Union forces there for the remainder of the year, and presented the Confederate government time to consolidate its manpower. With the new year, preparations for the Union campaign of 1862 were urged forward by the Federal government, impatient for an advance on Richmond. Following the withdrawal of the Army of Northern Virginia, under Maj. Gen. Joseph E. Johnston, south of the Rappahannock River, Maj. Gen. George B. McClellan revised plans for the spring offensive. As part of his Peninsula Campaign, McClellan ordered his army—the Army of the Potomac—to disembark for Fort Monroe from Alexandria, Virginia, and Annapolis, Maryland, on March 17, 1862. McClellan sought to turn on Johnston's position and advance toward Richmond before the Confederates could readily defend their capital.

As McClellan's plans were gradually revealed to the Confederates, the mass of Johnston's army was ordered to the Peninsula by early April. Magruder's Army of the Peninsula—about 13,600 men—was tasked with delaying McClellan's 121,500-man force. Finding that his advanced line required more force than was at his command, Magruder fell back behind the Warwick River to his secondary position, the Warwick Line. He described his position:

Two garrisons, amounting to 6,000 men, were stationed at Gloucester Point and Mulberry Island with heavy artillery to block Union passage of the York and James Rivers.