Carlow is a difficult place to find baptism records for.
www.irishgenealogy.ie has some Carlow records and some
records for the West of Wicklow along border areas.

Anne Mathers of Cronasdagh House, Mullin married farmer
Samuel Cooper 26 Oct 1871.

Thomas Mathers born Dec 27_____ Fa: Peter & Mo. Mary

www.ipg-web.com + Carlow is one of the best county websites around.

I have some Jenkinson birth records from photocopies taken from the Church of Ireland's representative library in Dublin that I will take a look and see if any of the names
you mention are there.

The very best way to prove a relationship is the Parish records in person where you can relate people to each other much easier than other methods. However,C of I Kiltegan Parish baptism records do not start till 1883 but has marriages from 1845.

A Gentleman or Esquire was not Nobility but a person who could afford to be a Head Tenant, usually leasing sufficient land to subdivide and rent out to tenant occupiers and in this was earned his income and paid the rent to the Lessor. He would also likely to be Protestant rather than RC.

In this case William J. Westby. Parish of Kiltegan, Rathduffbeg in the Union of Baltinglass and he is
renting a house, outbuilding and land 313 acres 3 roods and 12 perches of this he rents 0.3.20 of land and a house to James Connor. www.askaboutireland.ie

There are Jenkinson's in Griffith Valuation in Carlow
in the Parish of Fennagh in Carlow, 2 x James,1 William.

There are a couple of Thomas Mathers as leasee and then having tenants, Parish Clonmore (PLU Shillelagh)

On a parish map website Kiltegan Parish is on the border with Carlow but Fennagh Parish is one parish over, Tullowphelim being the parish bordering Kiltegan.

There is a not for profit History Foundation who has a database for most Irish Counties to which Wicklow belongs but not Carlow. There is a fee, but there is little in Ireland that is free.
The only birth recorded for Thomas Mathers is 1712 in Wicklow and no record of marriage and also the Griffith Valuation - found free elsewhere.

Depending when the marriage took place you might find records from 1864+ on www.familysearch.org or
on their old website - a link through the new website
and look for "go to previous site".

Annette Code