eigne

eldest; firstborn

Because the canon law (following the civil) did allow such bastard eignè to be legitimate, on the subsequent marriage of his mother: and therefore the laws of England (though they would not admit either the civil or canon law to rule the inheritance of this kingdom, yet) paid such a regard to a person thus peculiarly circumstanced, that, after the land had descended to his issue, they would not unravel the matter again, and suffer his estate to be shaken.

entailed; belonging to the eldest son