The town has been named,Diptiacum in 899, (Cartulary of Saint-Amand,Miroeus),Diptiacum in 906,Diciacum in 1097,Diptiacum in 1107,Dichis in 1181 (Chronique Gislebert),Dici in 1205[5]
It probably comes from an old*Deppiacum, based of the gallic nameDeppios[6] followed from the suffix-acum[7] (from the gallic-acon) of location and property, with the global meaning « property, farm of Deppios ». The suffix-(i)acum has generally finished as-y in the North (-ecque in the previous dutch speaking area and-eke in flemish), the plural form, appeared later-iacas to-ies.
Thearcheological statistics of the Nord departement of 1867 indicate:[8]
Since 7th century, Dechy containing maybeFérin belonged to the Saint-Amand Abbay. The count ofOstrevent hadadvocatus that was explaining Dechy and Férin of Hainaut county, although near ofDouai.
Anhospital was already existing in 1218, the patient care were made by the sisters of the Abbaye of Beaulieu in Sin-le-Noble[9]
In 1205, the abbe Jean gives to hisvassals of Dechy and Férin a penal law copied of the one in Douai.