Located along the Line Wall Curtain, originally the old medieval defensive walls stretching all the way from the City to Europa Point. North Jumper’s Bastion is sited over the earlier Spanish Baluarte de Santa Cruz [Bastion of the Holy Cross], designed by the Florentine military architect, Giovan Giacomo Paleari Fratino, and completed in 1575.
Originally, the Baluarte de Santa Cruz had been one of a number of old Moorish towers built along the entire length of the western littoral of the Rock that stretched from North Bastion to Europa Point. This crenellated wall was roughly nine feet thick and twenty-five feet in height. This wall and intermittent towers can clearly be see in Anton van den Wyngaerde 1567 sketches as well as in Cristóbal Rojas’s 1608 map of Gibraltar. Riojas identifies ten such defensive watchtowers protecting the western approaches to the Red Sands area, including a platform for guns which later became the Baluarte de Santa Cruz.
Wyngaerde notes in his sketch that this stretch of curtain wall was where the Castillian nobleman Enrique Pérez de Guzmán, 2nd Count de Niebla drowned in his failed attempt to capture the stronghold of Gibraltar from the Moors in 1436. His body was later recovered by the Moors and placed it in a basket and hung it from one of the castle's turrets. It would remain there until 1462 when Gibraltar was finally captured during Gibraltar´s Eighth Siege. One of Gibraltar's gateways was named after the barcina, or wicker basket, in which Niebla´s body was displayed.