What is the most famous artillery in London? The Yeoman of the Guard’s pike? The four Mk XXIII 50 calibre BL 6in triple turrets atop HMS Belfast ? Certainly one of the most enigmatic weapons is St Mary Axe, which gives its name to the Swiss Re building ( aka the Gherkin, aka 30 St Mary Axe ) and was derived from the name of church on the City site.

Conflicting stories linger about the axe. One version refers to a legend of an English king in the fifth century Dionotus of Dumnonia who allowed his daughter Ursula, 11, on a pilgrimage to meet her husband near Cologne with 11,000 young handmaidens – the number a likely mistranslation or an extrapolation from the age of the princess.

While journeying on the Lower Rhine they encountered Attila the Hun who beheaded all the holy virgins with three axes, making them martyrs. The full title of the City church, which was converted into a warehouse in 1560, has been cited as St Mary the Virgin and St Ursula and the 11,000 Virgins.

A 1514 manuscript says that the church contained a holy relic – an axe used by the Huns to execute the virgins while the Basilica of St Ursula in Cologne contains the alleged relics of Ursula and her 11,000 companions, including various human bones.

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Another line of thought suggests a more prosaic reason for the axe. The church was dedicated to the Virgin Mary, and the axe came either from the neighbouring tavern, which carried an axe on its sign, or from the regular church goers who were from the Worshipful Company of Skinners, who attached their emblem, including an axe, to the church.

John Strype writes in A Survey Of The Cities of London and Westminster (1720): “In St Mary Street had ye (of old time) a Parish Church of St Mary the Virgin, St. Ursula, and the 11000 Virgins; which Church was commonly called St. Mary at the Axe, of the Sign of an Axe.”