Seventy years ago, the owner of a Suffolk estate invited guests to celebrate the unearthing of a 'Viking' ship on her land. Little did she know it would turn out to be one of the most important Anglo-Saxon finds of the century.

The sherry party that Mrs Edith Pretty threw at her home above the River Deben in Suffolk on July 25 1939 was one of those occasions that everyone remembers for the wrong reasons. The invitation, dispatched to the great and good of the locality – including the curator of the Ipswich Museum and the Lord Lieutenant of Suffolk – was to celebrate the discovery of a "Viking ship" buried on her land. Along with the sherry, there was to be a lecture by Charles Philips of Cambridge University, who was the leading archaeologist on the dig.

Unknown to Mrs Pretty, as she was assembling her guest list, the ship – hitherto a collection of iron rivets and ghostly ribs of sand – had suddenly yielded a startling secret. At the centre of its hull lay a 1,400-year-old burial chamber containing the funerary objects of a great king. There was corroded evidence of a magnificent helmet and sword; there were fragments of textiles and the remains of a beautiful lyre. There was gold, there were garnets, there was cloisonné; there was enough to keep headline writers busy for weeks. It was to be the find of the century. And the local press were about to turn up.

The National Trust shares its responsibilities with the Sutton Hoo Society; the latter does site tours while Trust volunteers man the exhibition that occupies a grey timber building 10 minutes' walk away. Wainwright helped set up the exhibition: to their horror, the researchers found that most visitors knew nothing at all about the Anglo-Saxons. The originators of so much English culture – place names, kingship, legal system – had somehow been squeezed out by the sexier Romans and Vikings. Their delicate interlaced designs were assumed to be Celtic. Even now, some people still leave thinking that Sutton Hoo contained a Viking ship.