Why is County Waterford known as "The Diese County"?

Question

If there are any native speakers could you please tell me what the word "Diese" refers to.

Answer 1

I live in Waterford  ...  A tribe called the Deise,  driven from Tara, conquered and settled in the area now known as Co. Waterford. Originally referred to as Deise Muman. The eastern part of the county came under the control of the Le Poers, or Powers, family, and the western part, called the Decies, came under a branch of the Fitzgeralds. The county Motto is "Up Declan and the Deise" (where Declan is St. Declan).

Up the Deise!

Answer 2

County Waterford is known locally as "The Decies" (An Déise). Some time between the 4th and 8th centuries, a tribe of native Gaelic people called the Déisi were driven from the southern parts of the country, conquering and settling here. The ancient principality of the Déise is today roughly coterminous with the current Roman Catholic Diocese of Waterford and Lismore. The Deise has a rich history from megalithic tombs and ogham stones, to Vikings, to remnants of English occupancy, including the Gaulstown dolmen, Reginalds Tower and the Ballysaggartmore Towers respectively.

Answer 3

The Deise (pronounced 'day-she') were a tribe that settled in what is now Waterford.

Answer 4

'Diese' is german for 'this', but as it's in ireland I guess that doesn't help. I did however find this on wikipedia:

The Déise

County Waterford is known locally as "The Decies" (An Déise). Some time between the 4th and 8th centuries, a tribe of native Gaelic people called the Déisi were driven from the southern parts of the country, conquering and settling here. The ancient principality of the Déise is today roughly coterminous with the current Roman Catholic Diocese of Waterford and Lismore. The Deise has a rich history from megalithic tombs and ogham stones, to Vikings, to remnants of English occupancy, including the Gaulstown dolmen, Reginalds Tower and the Ballysaggartmore Towers respectively.

....and this more easily understandable excerpt from a book:

Decies

Native Gaelic peoples called the Deisi, who were driven from Tara, conquered and settled in the area now known as Co. Waterford. Originally referred to as Deise Muman, the area between the River Blackwater and the River Suir is still today called "The Decies". Waterford city, of Norse foundation and an important port and centre of trade, was a bridgehead for the Anglo-Normans in the 12th century. The eastern part of the county came under the control of the Le Poers, or Powers, family, and the western part, called the Decies, came under a branch of the Fitzgeralds. The native Irish character of the population was never wholly obliterated; and in the west, near Dungarvan, Gaelic continued to be spoken into the 20th century.

Answer 5

I was going to answer this but Celery has answered it perfectly. She wins the cigar. There is nothing extra I could add.