Year of birth is a guesstimate source: The Families of Jacob by A.H.Jacob and J.H.Glascott, Dublin 1875 Irish Ancestor Vol 2 p122 gives extract of will, proved 1 Jan 1668, Ferns. Left land at Sigginstown to John and at Churchtown to Austen. Chattels to wife Dorothey. Extract from the Families of Jacob The founder of the Irish branches of the family of the Cambridgeshire Jacobs was a Lieutenant William Jacob, who settled at Sigginstown, in the barony of Forth, and of who we shall speak presently. His father was John Jacob Esq of London (circa 1565-1640), a brother of Abraham Jacob of Bromley, who was father of Sir John Jacob, the first baronet, and a younger son of Robert Jacob of Gamlingay, who died in the early part of the seventeenth century. This John Jacob Esq of London was a merchant in the latter part of the reign of James 1. He married into a family named Halliday, probably the same as that of the Lord Mayor of London, whose daughter was Sir John Jacob's first wife, and by her he had three sons, all of whom settled in Ireland, two of them at least being officers in the army. His third son was Robert Jacob Esq., who was an officer in Col Saunders' regiment. He was granted by the Crown certain lands (114 acres) of the value of £67 yearly in the barony of Scarawalsh and county of Wexford, which were the sequestered property of of one Edward Synnott, a participator in the rebellion of 1641. This Robert appears to have never married, and he died without issue, leaving his property above-mentioned to his fourth brother, Arthur Jacob of Knockduff in the county of Wexford, who after his brother's death petitioned for a continuance of the grant of lands, and was successful. He was married and died in intestate, and administration was granted to his widow on the 19th March 1720. Thus three of the sons of John Jacob, the London merchant, uncle of Sir John Jacob of Bromley, died without leaving heirs male. The remaining son, the eldest, was William Jacob Esq (circa 1610-1688), a lieutenant in Cromwell's army. The lands of Sigginstown, in the barony of Forth were on the 22nd June 1667 granted to him in consideration of his military services. This property consisted of '533 acres, ? rods and 28 perches plantation measure or 864 acres and 34 perches statute measure The property had previously been the property of the old Anglo-Norman family of Siggin, who had settled there after Strongbow's invasion 1172.

source: The Families of Jacob by A.H.Jacob and J.H.Glascott, Dublin 1875 of Horsemonden Parish, Kent