There was a fortification at Framlingham long before the Normans arrived, perhaps as early as the sixth century, and King Edmund is said to have met the Danes nearby in battle and afterward sought protection at Framlingham. He later fled from this stronghold and was captured and murdered in the forests nearby. Before the Domesday Book (1086), it was held by Aelmer, a Thane, and consisted of 24 villagers with a total value of £16. After Domesday, under Roger Bigod it had risen to 32 villagers with a value of £36. Excavations for a drain at Framlingham in 1953 uncovered 25 skeletons, some with 8th century dress ornaments, which are thought to belong to a Saxon cemetery.

Framlingham was administered mostly through relatives of the crown until the 14th Century, when it became the property of the Mowbray family after Thomas Mowbray was made the First Duke of Norfolk by Richard II in 1397. Mowbray, who was also Earl of Nottingham and Earl Marshall of England, was given Framlingham and other estates. including Arundel, but he died in exile. Thomasís eldest son, Thomas, Earl Marshall and Third Earl of Nottingham, was executed for rebellion against Henry V.

Thomasís second son, John, was recognized as Duke in 1425 and often lived at Framlingham Castle as did his son and grandson in succession.

The Mowbray estates all eventually rested with Ann Mowbray, who was born at Framlingham. Ann was seven years old when she was betrothed to Prince Edward (age 12), one of the two Princes reputedly murdered in the Tower of London [Edward V of England (4 November , 1470 Ė 1483?) and his brother, Richard of Shrewsbury, 1st Duke of York (17 August 1473 Ė 1483?), were the only sons of Edward IV of England and Elizabeth Woodville.] Anne died a couple of months after the betrothal, and the Berkeley and Howard heirs of her motherís family each received half of the huge Mowbray estate, with Framlingham passing to the Howard family. (Annís remains are entombed in Westminster Abbey, as are the remains of the two princes.) Despite being one of a number of properties owned by the new Dukes of Norfolk, Framlingham Castle, because it was not as elaborate as their other residences, was seldom used, but John Howard repaired the royal castle at Framlingham before his death.

The main entrance was altered and the bridge built by the 3rd (Howard) duke, and the ornamental chimneys on most of the towers were added in the 16th century to make the place look more like a house than a stone fortress. The castle took no part in the Civil War and, as a result, its battlements are well preserved. In 1636 the castle was bequeathed to Pembroke College, Cambridge, with the proviso that all of the interior buildings should be demolished and a poor-house built on the site. The original Norman Great Hall, built by the Bigod family along the western curtain wall, was incorporated into the structure of the poor house. The Poor House lasted for 200 years, and the castle was then used as a county court.

Today, Framlingham looks from the outside almost exactly as it did when it was built over 700 years ago, except for the ornamental chimneys. The continuous curtain wall linking 13 towers can be climbed and walked, giving excellent views of the surrounding countryside and town of Framlingham. The castle lies to the north of the town, beyond the parish church which contains some fine tombs of the Norfolk family. The curtain wall is in good condition, but nothing of the original buildings remains inside except the Poor House and a few outbuildings.