Strangford’s Viking name means ‘strang fjord’ describing the dangerously racing tides of the narrows. In recent times this name has started to be used for the Loch Cuan itself. Local Gaelic speakers still refer to the Lough as ‘Loch Cuan’.
Ardglass is at the centre of the ‘Lecale Coast’ which runs from Dundrum to the Mouth of the Quoile river and Strangford Lough. This area is full of visitor attractions, many of which can be seen at http://www.strangfordlough.org/
Lecale comes from the division of the Dál Fiatach clann of this area into three ‘halfs’ around 700AD with ‘Leath Cathail’ being ‘Cathals Half. The Dál Fiatach were the traditional Kings of Ulster known then as Ulaid/Uladh and based in Downpatrick. (in those days ‘Dún Lethglaise’).
When Patrick came to Ireland in 432, strong currents swept his boat through the Strangford Lough tidal narrows and he landed where the Slaney River flows into the lough just below present day Raholp. The local Dal Fiatach chieftain, Dichu Mac Trichim, was quickly converted and gave him a barn for holding services called ‘Sabhall Phádraig’, meaning "Patrick's barn” to this day.
572 Báetán mac Cairill the Uliad/Dál Fiatach leader was also high-king of Ireland and Scotland and his fleets in Loch Cuan/Strangford. The Ulaid kept their their fleets here for least the time of the Vikings, 400 years later. They lost control in Scotland in 637 at the naval battle of the Mull of Kintyre against the O'Neills and the survivors limped back to Loch Cuan/Strangford
The Vikings started attacking the Uliad kingdom in 795, and made several attempts at conquest but never managed to establish a long-term base. (see detail on Ardglass History on this site). Cathal mac Tommaltaig of the Leath Cathail branch of the Dál Fiatach (IE Cathal of Lecale, modern County Down) who was slain by the Norse in 853.
Famously the Ulaid had a naval victory over Sitrics Dublin Viking fleet South of Ardglass in 1022, after which many Norse crews and ships were taken prisoner. Niall then gathered his forces in Downpatrick (Dún Lethglaise at the time) in 1026 and sailed from the Loch to attack Dublin, devastating the Viking city.
The Dál Fiatach of Lecale also slew Magnus III king of Norway in 1103 who was raiding Lecale, but was ambushed by the Ulaidh near Downpatrick.
The Vikings spoke Norse, which contributed a quantity of loan-words to Gaelic, but in Down almost the only lasting records of their presence is Gunns Island in Ballyhornan and the Narrows at Strangford. This contrasts to the extensive place-name landscape which they bequeathed to northern and western Scotland and the Isle of Man.
The Ulaid left us most of the place names in Lecale as well as many modern surnames likeDunleavy, Haughey, O'Hoey, Hoy, Livingstone, McNulty, McAntamly, MacAnulty, MacAnley, McAlerney, McCaughey, O'Garvey, O'Lowry, Lynch or O'Luingsigh, the MacMahons or O'Mahon, O'Hughes O'Downey or O'Devaney O'Doolan,, Breasail ,O'Coulter , O'Flinn, McGee, O'Kelly, MacCool, McEwen, the Scottish McLachlans and the Irish McSweenys. and many more including the British House of Stuart which is also descended from the Ulaidh. There are 500 Magees and MacCartans alone on the Lecale electoral register.
Norman names are also very common locally. The Norman-Irish surname Fitzsimons shows 345 entries on the electoral register. The Fitzsimons' along with the Savages of Portaferry one of the first Norman settler families in Lecale.