However, two of the side chapels have been refurbished in highly contemporary style, with modern altars, and abstract artistic decoration and religious symbolism.

The cathedral contains the tombs of Charles IX of Sweden, Sten Sture the Elder, Maria of Palatinate-Simmern and Gustaf Otto Stenbock.

On 31 July 2018, the burial regalia (two crowns and an orb) of Charles IX and Christina of Holstein-Gottorp were stolen in a daylight robbery with the thieves escaping by boat.

It dates its origin to the year 1316 when Strängnäs Dominican monastery (according to a record kept by a will) received a widow's donation of books.

Dr Henrik Aminson (1814-1885) published in 1863 a comprehensive printed directory Bibliotheca Templi Cathedralis Stregnensis, quae maximam partem ex Germania Capta est circa finem belli triginta annorum, descripta, 1-2, of over 600 pages.