[8] In 1675 the court commissioner of buildings Michael Springrueber approached Hofkriegsrat Guidobald Franz Freiherr von Hegi with a proposal to improve the fortifications protecting the central areas of Salzburg city, cutting the Mönchsberg ridge in two, and connecting the parts with a drawbridge.

This would prevent any enemy that had succeeded in taking the Monika and Augustiner forts from making its way along the Mönchsberg right up to the outer works of the castle and from bombarding the old town from the heights.

[citation needed] In 1676 Hegi made the same proposal to the Prince-Archbishop of Salzburg, Max Gandolph von Küenburg and set out to see whether the Mönchsberg could indeed be cut at its narrowest point.

The valley lowlands of Riedenburg could be made accessible by means of the cut and could allow room for settlers from the old town; the new district would also be militarily easy to secure.

[citation needed] From 1676 until Max Galdolph's death in 1687 excavations proceeded and a 35m wide cut was made in the mountain from its eastern side before work was abandoned as uneconomical.

[10] At the tunnel entrance on the old town side an inscription was carved over a bas-relief of the Prince-Archbishop with the words Te saxa loquuntur ('The stones will speak of you').

Originally the structure of the baroque horsepond with its frescoes extended in front of the current eastern gate, giving the square a symmetrical form.

SIgIsMVnDI ArChIepIsCopI SaLzVrgensIs P(rincepis) S(acri) R(omani imperii) comitib(us) de Schrattenbach aeternae memoriae W(olfgangus) Hagenauer archit(ectus)'.

[citation needed] The original plan included the construction of a military outer structure on the Riedenburg side, disguised as a park of 'ruins', then fashionable.