Nor Loch

The depression, along with the parallel one now occupied by the Cowgate, was formed by glacial erosion during the last Ice Age, when the icepack was forced to divide by the volcanic plug now known as Castle Rock.

[1] The loch was formed by creating an earthen dam to block the progress of the Tummel Burn, a stream that ran along the foot of the north side of the castle rock.

In the winter of 1571, as part of a plan to end the "Lang Siege", the Earl of Morton explained that, "One side of the town is 'unwallit', and the frost may give occasion to assault it that way with far less difficulty than otherwise", suggesting that the requested English army could cross the frozen Loch.

[4] As the Old Town became ever more crowded during the Middle Ages, the Nor Loch became similarly polluted, by sewage, household waste, and general detritus thrown down the hillside.

The Nor Loch fulfilled a variety of other roles during this period including: However, in 1685, the law of Scotland outlawed drowning as a form of execution.

James Skene of Rubislaw, who was present at the work in the gardens, reported that the skeleton of a tall man was found between those of two women.

Draining of the western end was undertaken 1813 to 1820, under supervision by the engineer James Jardine to enable the creation of Princes Street Gardens.

[1] The Nor Loch was never a source of drinking water, and indeed was probably highly polluted, being largely stagnant and used as a dumping ground for rubbish over and above being the termination point of many of the Old Town's open sewers.