The period between 1214-1216 was a particularly difficult one for King John: most of his country was occupied by the French King, Louis VIII The Lion (who had been declared King in London), even his most ardent supporters were deserting John’s side, the Barons forced him to sign Magna Carta, the Pope issued a proclamation whereby anyone who tried to seize the Crown from John would be entitled to do so, John fell ill and suffered from dysentery, and to top it all, he lost the Crown Jewels.
In 1216, King John travelled to Bishops Lynn in Norfolk where he arrived on October 9. Unfortunately, he fell ill immediately upon arrival and it was decided he would return to Newark Castle, which was deemed safer (the threat of Louis VIII was hovering in the air). It is assumed that the King took the slower and safer route around the Wash, aptly named so because it was full of marshes and dangerous flats. However, most of his soldiers and several carts full of his personal possessions, including the crown jewels he had inherited from his grandmother, took the shorter route through the marshes. This route was usable only at low tide. The horse-drawn wagons moved too slowly for the incoming tide, and many were lost. The treasure carts were lost and never recovered.