The siege in particular had a significant impact on Lisbon because of the ongoing Christian and Muslim conflicts on the Iberian Peninsula.

In 1109 a Norwegian fleet of 60 ships entered Lisbon through the Tagus river under the command of Sigurd I of Norway.

[1] There, they would eventually besiege the city and hand it over to the Christian Kingdom of León through their vassal and Henry, Count of Portugal.

The Norwegian army, with Sigurd the Crusader at its head, plundered and seized the city successfully.

Evidence points to there being some sort of agreement between Sigurd and Count Henry of Portugal; however, there are no direct records of the alliance.