The surname of AMBROSIUS is of Italian origin, a baptismal name 'the son of Ambrose' a name meaning immortal. After the Crusades in Europe, in the 11th 12th and 13th century people began, perhaps unconsciously, to feel the need of a family name, or at least a name in addition to the simple one that had been possessed from birth. The nobles and upper classes, especially those who went on the Crusades, observed the prestige and practical value of an added name, and were quick to take a surname. The name is also spelt AMBROSIA and AMBROSI. ST. AMBROSE (c.339-397) Roman official and Christian prelate. He was governor of Liguria (in northern Italy) when (37l) the bishop of Milan died. Rival factions being unable to agree on a successor, Ambrose was himself elected even though not yet baptized . As bishop he proved himself a brilliant administrator and a courageous opponent of Arianism which the Emperor Theodosius supported. He held that the church alone was guardian of moral and religious truth and even went so far as to excommunicate the emperor for his massacre of the Thessalonians. He wrote many hymns and introduced the 'Ambrosian chant' and much ritual into church services. The Ambrosian library at Milan is named after him. The origins of Italian surnames are not clear, and much work remains to be done on medieval Italian records. It seems that fixed bynames, in some cases hereditary, were in use in the Venetian Republic by the end of the 10th century. The typical Italian surname endings are 'i' and 'o', the former being characteristic of northern Italy. The singular form 'o' is more typical of southern Italy. At first the coat of arms was a practical matter which served a function on the battlefield and in tournaments. With his helmet covering his face, and armour encasing the knight from head to foot, the only means of identification for his followers, was the insignia painted on his shield, and embroidered on his surcoat, the draped and flowing garment worn over the armour. The associated coat of arms is recorded in Rietstaps Armorial General. Registered in Italy. (Ambrosini).