The surname of AGIUS was derived from the Old French Agace, the vernacular form of the learned Agatha, from the Greek 'AyaOoc' meaning good. The name was probably brought to England in the wake of the Norman Conquest of 1066. The Norman Conquest in the year of 1066 revolutionized our personal nomenclature. The old English name system was gradually broken up and old English names became less common and were replaced by new names from the continent. Most of the early documents deal with the upper classes who realised that an additional name added prestige and practical advantage to their status. Names of peasants rarely occurred in medieval documents.

Early records of the name mention Robertus filius Agacie, 1279, Canterbury. Roger Agace, 1275, County Surrey. Thomas Agas was documented in County Sussex in the year 1480. The name has many variant spellings which include Agass, Aggas, Aggass, Aggus and Aguss. 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. When the coast of England was invaded by William The Conqueror in the year 1066, the Normans brought with them a store of French personal names, which soon, more or less, entirely replaced the traditional more varied Old English personal names, at least among the upper and middle classes. A century of so later, given names of the principal saints of the Christian church began to be used. It is from these two types of given name that the majority of the English patronymic surnames are derived and used to this day.