During a particularly dire moment of the siege, Ancona inhabitants staged a short sortie and managed to throw a barrel containing resin and pitch in front of the besiegers - but it was very dangerous to light it.
It was at this moment that the widow Stamira boldly came out of the walls, wielding an ax with which she broke the barrel and set it on fire, thus destroying part of the besiegers' war machines – but at the price of herself being killed.
The events of the 1173 siege – including Stamira's heroic act – were narrated some years later, in 1204, by Boncompagno da Signa, in the Liber de Obsidione Anconae.
She is the widow of Pietro Stamura, a Milanese citizen, who for being opposed to the troops of Barbarossa, was brutally tortured and killed together with other Lombard patriots.
At the time of her heroic self-sacrifice, Maria Stamura is engaged to Guglielmo Gosia, son of Martino, Mayor of Ancona, and is a friend of the priest Don Giovanni da Chiò, another hero of the siege of 1173.
Due to the great popularity of Cannonieri's work, especially widely disseminated in mid-Nineteenth Century Italy, “Stamura” was the commonly accepted version of her name.
In 1936 Palermo Giangiacomi, self-taught historian and Ancona City Councilor, convinced the municipal administration to accordingly change the name in the public locations commemorating her.