1) Chief Captain of Ireland

In 1494, Gilbert Nugent, Baron of Delvin,was appointed Chief Captain of the King Henry VII forces in Ireland, at a salary of £200 a year,6 on June 25, three days after the entries of payment of army wages in Hattecliffe's accounts stop. 

According to the history of Henry VII's Relations with Scotland and Ireland 1485–1498
By Agnes Conway

2) Chief of all Irish forces of Dublin, Meath, Kildare, and Louth. 

RICHARD, 7th baron, had summonses to parliament in the years 1486, 1490, 1493, and 1498 and was constituted by the lord justices and council in 1496 as Commander and Leader in  Chief of all forces of Dublin, Meath, Kildare, and Louth.  

3) William Nugent, Baron Delvin - was Sheriff of Meath 1401

4) Christopher 8th Baron Delvin  - 1593 - Chief of Forces in Westmeath -  Summoned Parliament in 1585

To clarify, Sleught William (sometimes spelled Sleughte William or Sleught), also referred to as Clan Liam in some historical sources, was an important Gaelic group in the Annaly region (modern-day County Longford). This clan, or group, was led by the Delvin family in the context of the hereditary captaincy that was granted to them by the English Crown.

Key Points about Sleught William (or Sleughte William):

1. Sleught William (or Sleughte William) was a Gaelic term referring to a military host or clan in the Annaly region of Ireland.

2. The Delvin family, as Barons of Delvin, were appointed hereditary captains of this clan. This gave them the authority over the Sleught William (or Sleughte William) clan, which was an important Gaelic faction in the Westmeath and Longford areas.

3. This position as captain was hereditary, meaning it was passed down through the generations of the Delvin family, and they held significant influence over the local Gaelic tribes in the region, balancing their power with the authority of the English Crown.

4. The Sleught William or Sleughte William clan was part of the broader Gaelic resistance to English control during the 15th and 16th centuries, but the Delvins, as Anglo-Irish nobles, were aligned with English rule, leading to their role as captains over the clan.

Conclusion:

Sleught William (or Sleughte William) refers to the Gaelic clan or military group associated with the Annaly region, and the Delvin family held the hereditary captaincy over this clan. Their role as both Barons of Delvin and captains of Sleught William solidified their control over the region and their important position within the Anglo-Irish power structure.