[uncertain] what is?

Question

My question is in regards to Elizabeth Bourchier-39.  I was wondering if someone who is pre-1500 certified could take a look at why she has an [uncertain] tag.

I believe it may have to do with parentage of her daughter Elizabeth Page. Sources I have found to verify her parents include pg 668, Vol. II Royal Ancestry, 

pg. 7, Nottinghamshire Visitation

https://www.ancestry.com/imageviewer/collections/6621/images/UKI1-Nttnghm-1569-NTTNGHM-0015?ssrc=&backlabel=Return&pId=16

pg. xxxi, Literary Remains of King Edward VI https://www.google.com/books/edition/Literary_Remains_of_King_Edward_the_Sixt/7TUJAAAAQAAJ?hl=en&gbpv=1&bsq=%22richard+page%22+%22elizabeth+bourchier%22&pg=PR31&printsec=frontcover 

pg. 104, History of Ormsby lists her father as Richard Page. https://www.ancestry.com/imageviewer/collections/20495/images/dvm_GenMono004772-00059-0?pId=112

I see on her wiki page the Skipwith Pedigree from Visitation of County of Lincoln list her father as William Page. Is that one source enough to make her parentage uncertain?

Comments

Because the relationship is marked as uncertain (see in edit mode, on the right).

All my own family relationships are marked confident, because that's what I know.

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I have added an estimated year of birth of 1515 for Elizabeth Page.

https://www.wikitree.com/wiki/Page-3577

Please feel free to develop the profile further and then you can take a view on whether the identity of her mother is uncertain or not.

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For clarity, the Uncertain tag relates to her being mother of Elizabeth Page, not to her own parentage.