A map of the Stadsholmen from the 1650s, illustrates de la Vallées suggestion for the conversion of the old castle. The project also brought about an adjustment of the Slottsbacken, making it partially enclosed by buildings. Of interest are Tessin the Younger's additions in pencil on that map, probably made at the end of the 17th century. There is an early sketch for the northern facade's west wing and the two curved wings enclosing the outer courtyard (both executed). Tessin the Younger also made plans for the city area west of the palace with large stairs in false perspective where the Axel Oxenstierna palace, among other buildings, are and joining the Västerlånggatan in addition to a wide street to the present Mynttorget, straight though the city block with the present Brantingtorget (not executed). He had envisioned a line of sight from the center of the palace, westwards to the Riddarholmen.