Byrhtnoth (Old English: Byrhtnōð; c. 931 – 11 August 991) was a 10th-century Anglo-Saxon magnate who governed as the ealdorman of Essex from late 956 until he died in battle. Byrhtnoth was initially appointed by King Eadwig and supported the young ruler, but after the kingdom was partitioned in 957, he and his lands were under Eadwig's younger brother Edgar, who was ruling England north of the Thames. After Eadwig died, the kingdom was unified, and Byrhtnoth was one of four leaders of Edgar's administration, alongside Æthelwine of East Anglia, Ælfhere of Mercia, and Oslac of York. Byrhtnoth was one of the wealthiest men in the kingdom and a prolific supporter of monasticism, causing monastic writers to celebrate his piety. There was disorder after Edgar's death, with a large-scale reclamation of land from the monasteries. Byrhtferth of Ramsey praised Byrhtnoth and Æthelwine for their defence of the monasteries Edgar's teenage son Edward replaced him after a power struggle, and Byrhtnoth was loyal to the young king, but Edward was murdered in 978. He was succeeded by his younger brother Æthelred, who was crowned after a year. Byrhtnoth was an experienced ealdorman under Æthelred, and Æthelwine's illness in 991 made Byrhtnoth the most senior ealdorman in England.
After a lull lasting decades, Viking attacks started up again in the 980s, commencing the so-called "Second Viking Age". Raids took place from 980–982 and in 988, but these early attacks do not seem to penetrate far. A band of Vikings probably led by Olaf Tryggvason landed on English shores in 991, devastating Ipswich, and Byrhtnoth marched out to meet them at the Battle of Maldon. He seems to have been greatly outnumbered, but the Vikings were contained on a causeway, which the more professional troops among Byrhtnoth's host could defend easily. Byrhtnoth gave up this advantage to meet the Vikings directly in battle, and in the ensuing engagement he was defeated and killed.
Byrhtnoth was celebrated for his bravery and religiosity in the accounts of the battle by monastic chroniclers as well as the poet of The Battle of Maldon, which is our main source on the engagement. However, the poem implies criticism of his decision to fight the Vikings on equal terms. Later scholars disagree on this decision, with some being condemnatory, and others arguing that the Vikings had to be destroyed there unless they plunder elsewhere. Byrhtnoth was also known for his immense size; earlier estimates placed him at 6 ft 9 in (2.06 m), but he was probably just over six feet. He is the subject of J.R.R. Tolkien's short play in verse, The Homecoming of Beorhtnoth, Beorhthelm's Son; and a modern statue at Maldon.