This interesting name is characteristically Irish, although in some rare instances there is a possible derivation from the Norman French topographical name "del aunaie", meaning dweller by the alder grove. The Irish surname is also topographical in origin, being derived from the Irish words "dubh" meaning black, and "Slaine", a topographical name referring to the River Slaney in County Wexford; hence applied to the "swarthy or black dweller by the river Slaney". The surname was once spelled with an "O", as "O'Dubhshlainte", the prefix "O" indicating "son of", but it has been Anglicized as Delany, Delaney or Dulany. Topographical surnames were among the earliest created, since both natural and man-made features in the landscape provided easily recognisable distinguishing names in the small communities of the Middle Ages. This is a rare form of Irish surname, as traditionally they are taken from the heads of tribes, or from some illustrious warrior. One Felix O'Dulany was the bishop of Ossory from 1178 to 1202, who built St. Canice's cathedral in Kilkenny. The name is chiefly associated with the Irish Counties of Leix (Laois) and Kilkenny. A very early occurrence of the English derived Delany surname is found in the late 11th Century (see below). The first recorded spelling of the family name is shown to be that of William de Alno, which was dated 1086, in the Domesday Book, during the reign of King William 1, known as "William the Conqueror", 1066 - 1087. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.