Old Sarum Cathedral is on the site of the earliest settlement of Salisbury, in Wiltshire, England. Old Sarum is mentioned in some of the earliest records in the country. It sits on a hill about two miles north of modern Salisbury.

After the conquest of England, William the Conqueror and Lanfranc, the new Archbishop of Canterbury reorganised the English church. In 1075 a church council authorised the relocation of the bishopric (diocese) of Shurborne at Old Sarum.

Old Sarum Cathedral was built by Bishop Osmund, the kings nephew, which was consecrated in 1092. Just five days later, a great storm came and the building was largely destroyed by lightning. Reconstruction began in 1100, a year after Osmund's death. It was carried out under the new Chancellor, Roger of Caen, appointed by the newly crowned Henry I. In 1102, Roger was also named Bishop of Salisbury, and during his tenure, he accumulated great wealth and influence far beyond the boundaries of the town. Old Sarum reached the height of its authority and importance. Bishop Osmunds cathedral was quite small, Roger doubled the size between 1110 - 1135 by enlarging the transepts and adding a large eastern extension. The cathedral reached its greatest extent some fifty years later when Bishop Jocelyn de Bohun added a new west front with corner towers.

In 1139, four years after the death of Henry I, officers of King Stephen, who were distrustful of Roger's power, arrested him, seizing his estates and castles. Roger died later that year of fever at Old Sarum. The city of Old Sarum went into a decline and tension developed between the civil and religious authorities, escalating over the next 50 years. The solution to the tension, proposed by Bishop Herbert Poore to Richard I in 1194, was to move the cathedral away from Old Sarum to a virgin site on the banks of the nearby River Avon. Richard approved the move and the plans were drawn up. The townspeople actually began to move to the new site before any official announcement was made.

Finally, in 1220, the new Salisbury Cathedral was begun. 38 years later it was compleated. Cathedrals were usually evolutionary structures developing over centuries and incorporating many different architectural styles. Salisbury Cathedral, by contrast, due to its relatively brief construction time, is a spectacular example of a single architectural style, known as Early English.

It wasn't until 1834 that people noticed marks in the grass. Excavations in 1912 - 14 revealed the foundations of the cathedral.