There have been two castles at Morpeth. The first was a motte-and-bailey thrown up in the 11th century on a hill overlooking the River Wansbeck. King John destroyed it in 1216, the same campaign in which his troops took Mitford Castle a few miles west. The site lay empty for over a century. Then in the 1340s a new castle was built within the bailey of the original. Little of that second castle survives - parts of the curtain wall, and a much-altered gatehouse. The motte still rises above the river, the medieval earthworks still legible in the land. The castle was held over the centuries through the female line of several illustrious families: de Merlay, Greystoke, Dacre, Howard. None resided there for long. It was always a possession, rarely a home.

In 1516, Margaret Tudor - sister of Henry VIII and widow of James IV of Scotland - fled across the border to escape her enemies in Scotland. Her brother offered sanctuary. She stayed four months at Morpeth Castle while arrangements were made. She was ill for much of that time. The castle was not luxurious, even by the rough standards of border holdings in the early Tudor period. Margaret was thirty-six years old, twice widowed in effect, the mother of a king she had been forced to leave behind. The view from her windows would have included the Wansbeck winding south, the market town clustered around the church, the same Northumbrian sky that hangs above Morpeth still. Eighty-two years later, in 1598, the constable Edward Grey captured Robert Crawforth and Valentine Thomas at the castle. They claimed to be involved in a plot to assassinate Elizabeth I.

The English Civil War swept through Northumberland in 1644, and Morpeth Castle, never a major fortress, found itself in the path of armies. A garrison of 500 Lowland Scots had taken it for Parliament. A Royalist force of 2,700 - more than five to one - laid siege. The defenders had inferior numbers, no certainty of relief, and a castle that was already two centuries old and never designed for serious artillery. They held for twenty days. In the end the castle fell, but the action had bought time and tied down Royalist troops. For most of its working life Morpeth Castle was a footnote, but for those three weeks it mattered to the outcome of a national war. After the war the structure declined further. In about 1860 the gatehouse was restored and converted into a staff residence.

In 1988 the Landmark Trust took a long-term lease on the castle. The Trust specialises in rescuing historic buildings by turning them into rentable accommodation - a strategy that funds the conservation. In 1990 they completed a refurbishment that stripped away modern extensions and a swimming pool, restoring many of the gatehouse's historic features. The result is a stone building that sleeps a small party in rooms where Margaret Tudor sheltered and Civil War defenders held the line. The civil parish of Morpeth Castle, which had existed in its own right since 1866, was abolished on 1 April 1935 and merged with Morpeth. The castle itself is now a Scheduled Ancient Monument and a Grade I listed building. You can climb the spiral stair, sleep in the gatehouse, look out at the River Wansbeck, and reflect that the previous tenant in your room may have been a Tudor princess.