Pietro Giovanni Guerri dall'Oro.

In 1862, Pietro Giovanni Guerri marries Dejanira dall'Oro (Padua/Treviso 1835 — 1900), last descendant of the House of dall'Oro, originally from Padua in the 13th century and later settled in Treviso.

In the absence of male heirs in the House of dall'Oro, Pietro Giovanni adds his wife's name to his own to perpetuate the name of the ancient Treviso family. From this union is born the compound surname Guerri dall'Oro, still borne today by the descent.

The arms adopted are quartered: in the 1st and 4th quarters the arms of the Guerri (a bend argent on a field vert, accompanied by six mullets or); in the 2nd and 3rd quarters the arms of the dall'Oro. The motto remains that of the dall'Oro: "Nihil ab auro potest qui aeternum non est".

From Pietro Giovanni and Dejanira is born Pietro Quinto Guerri dall'Oro (1874–1944), Colonel of the Carabinieri, married in 1908 to Elena Bisi (1886–1960). Their descendants, through Count Aldo Guerri dall'Oro, form the present-day family.