Iroise Sea - Name and Extent

Name and Extent

The name is first recorded in the Neptune francois of 1693 as Le Passage de l'Yroise (passage = "channel"); as Passage de l'Iroise in the 18th century; as Iroise in the 19th century; and as mer d'Iroise (mer = "sea") in the 1970s, by the seabed exploration industry. The name appears to have been fixed not by local seafarers but rather by the naval base at Brest. The 18th-century maps restrict "Passage de l'Iroise" to the channel leading north-west from Pointe Saint-Mathieu and keeping south of Ushant and the Ponant Islands. From the 19th century, Iroise encompasses all the sea the west coast of Brittany, between Ouessant and Sein. While this remains the limit used by mariners, some twentieth-century sources have used mer d'Iroise to denote the entire Celtic Sea as far as Ireland and England.

The meaning of Iroise is obscure; theories include:

• from the Old French Iroise meaning "Irish", denoting the route from France to Ireland
• from a dubious Old French adjective iroise meaning "angry", referring to the rough seas.
• from Breton hirgwaz; hir "long" + gwaz "stream, channel"
• From the Breton ervoas "deep", referring to the Atlantic Ocean, in contrast to the shallow English Channel

From the 1990s, "Iroise" became popular in Finistère in the name of many local businesses and associations. The Pont de l'Iroise bridge was opened in 1994.