I haven't found Adelicia de Verdon in the text for Barnwell (although Findagrave claims she was buried there, with no source given for validation).
Cawley claims:
[Pagan Peverell, whom he calls "Robert"] married ADELISA, daughter of ---.
Citing as proof for this claim:
“Willielmus Peverel de Brunne” donated property “in Wildene villa mea…Oddewic” to Thorney Monastery, for the souls of “avunculi mei Willielmi Peverel de Doure…patris mei Rodberti Peverel fratris sui, et Hamonis Peverel avunculi mei et…matris meæ Adeliciæ, et…Henrici Regis Angliæ” by undated charter[281].
The tricky phrase is "patris mei Rodberti Peverel fratris sui" (no commas). This phrase comes after "my uncle William Peverel de Doure".
Translated as a whole, in its entirety it should read: "my father's brother ROBERT Peverel his [meaning Uncle William's] brother".
Does it make sense that this donation did not mention the donor's father? Yes I think so, but only if the father was still living at the time of the undated donation. Because it was specifically intended to pay for prayers for the souls of deceased family members.
If the father was still living, this donor's father could have been PAGAN Peverel (and Adelisa Unknown would have been PAGAN's wife, not Robert's).
Yet, I can't seem to find this particular individual in the same textbook with Alice Pecche. But perhaps I am mistaken.
However (and this is why translating Old Latin is so rough for an amateur like me), if instead we chop the phrase up into much smaller units (patris mei -- Rodberti Peverel -- fratris sui)...then Google gives it a radically different meaning: "my father Robert Peverel his brother".
Which, lacking the proper punctuation, is borderline gibberish to my ears. That's why I lean toward feeding the whole phrase into the translator at the same time. But I could be mistaken, as I'm certainly no Latin scholar. I have to rely heavily on logic in order to compensate :D
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We know that Alice's brother was William Peverel, son of Pagan. In this record, assuming this is our William (I'm not 100% convinced) Adelicia Unknown is their mother. Which can only mean that at the time of this undated donation, their father, Pagan Peverel, was still living.
And Pagan Peverel had three deceased brothers (William Peverel de Doure, Robert Peverel, and Hamon Peverel) -- and a deceased wife, Adelicia/Adelisa Unknown. So he was likely aged at the time.
This undated record gives us:
PARENTS: Unknown Peverell who married Adelicia Unknown.
His father's brothers were: 1. "my uncle" William Peverel de Doure, 2. "my father's brother, ROBERT Peverel, his brother", and 3. "my uncle" Hamon Peverel.
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WILLIAM PEVEREL DE BRUNNE of Wildene (his village) in Oddwick, near Thorney Monastery (donor)
Did this donor have 4 sisters, one who was Alice, wife of Hamon de Pecche? Maybe so.
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I don't find this branch in the same textbook with Alice (Peverel) Pecche, and without further evidence would assume that they are cousins and that Cawley's source does not prove "Robert and Adelicia" as her parents. Nor "Pagan and Adelicia", for that matter. Because unless I'm mistaken or missed something, the locations don't seem to match up. However I have to admit my knowledge of English georgraphy and history is woeful indeed.