MYSTERY: Was Mary Skeen, the wife of Peter, Mary (Fitzsimmons), as shown undocumented on many Skeen family charts?   The use of this maiden name for Mary Skeen appears to have originated based on the following facts:  
(1) Peter Skeen was the administrator of the estate of Philip Fitzsimmon's widow, Mary Fitzsimmons, who died in 1800, by then also the widow of Wm. Toy.  
(2) Philip Fitzsimmons, of Worcester Twp. named a sister Mary in his 1770 will.  
A closer look at the will and estate papers of Philip Fitzsimmons. (1770-1807), and the estate records of Mary Fitzsimmons Toy (1800-1802), however, leave room for doubt about the assumption that Mary's  maiden name was Fitzsimmons.  There is no question that there was a connection between Peter and/or Mary Skeen to Mary, widow of Philip Fitzsimmons and Wm. Toy.  However, the stipulations of the will of Philip Fitzsimmons for his widow, six sisters, and minor dau., Ann, preclude his having a daughter Mary.  The married names of his sisters are given in none of the records, and Mary Skeen's age opens the possibility that she was a daughter of one of the sisters, with a different maiden name.  For these reasons we have shown her as Mary (     ).
(Phila. Co. Will Book M:50;   History of Worcester, 556 pgs., unindexed, owned by Barbara Wentz;   PA. AR., Vol. VIII⁷ "Marriage Records of the Swedes Church (Gloria Dei), Philadelphia, PA";  O'Brien, Michael J, Irish Settlers In America, Genealogylibrary.com; Phila. Co. Will Book O:499, written and proved 1770;  PA. AR., Third Series, Vol. XIV, Tax Lists, Worcester Twp.; PA. AR., Vol. IX ⁷ , "Marriage Records of Second Presbyterian Church, Philadelphia, 1774;   Phila. Co. Docket Book 10:210. Before court 12 Sep 1774: Petition for Guardian, LDS Film #0021845;   Mont. Co. Estate Files of Mary Toy, RW17015, OC19267;  Meier ²⁸, First Vol., pp. 18, 24.;   "Neighborhood News and Notices" from HSMC Bulletin V: 333: Sept. 7, 1807, settlement of estate of Philip Fitzsimmons.)

Clues for solving the Mystery:

1. Possibilities for Mary Skeen's identity:
As Mary Skeen was born in 1752, she would have been about 25 years younger than Philip Fitzsimmons, so it is possible she was his niece, and her maiden name not Fitzsimmons.  A family tie could have also been with Philip's wife Mary Fitzsimmons.  Philip first appears 1759-1761 as a Tavern owner and land holder in Providence Twp. and as a witness of Frederick Smith's will in 1759, Wife of Frederick, Mary and Henry Pawling of Providence Esq. Execs.; Other wits. Christian Recoup and Peter Bunn.  He was "of Providence" in 1763 when he buys land in Worcester Twp.  He moves to Worcester but keeps at least part of his land in Providence.   Was he the Philip who m. Mary Goldsmith in 1750?  And/or the Philip on the 1754 tax list of Maiden Creek Twp., Berks Co.? [Some marriages recorded as done in Philadelphia were actually done at St. Gabriel's, Berks Co.]    Was his brother-in-law Samuel Lewis a deceased sister's husband, a brother of Philip's wife, Mary, or married to his wife's sister?    SEE FAMILY OF SAMUEL RICHARDSON  [Family of Joseph Richardson.]
(Phila. Co. Will Book M:50; Worcester Historical Society, A History of Worcester Township, Boyertown Publ. Co, Boyertown, PA, 1976 1978, 556 pgs., unindexed, owned by Barbara Wentz;    PA. AR. Vol. VIII ⁷ "Marriage Records of Old Swede's Church (Gloria Dei), Philadelphia, PA";  O'Brien, Michael J, Irish Settlers In America, Genealogylibrary.com)

2. The will of Philip Fitzsimmons:
Included a desire to be buried in the Catholic Cemetery in Philadelphia. and wife Mary, and Joseph Cauffman of Phila. to be executors;  legatees were wife Mary... a minor daughter, Ann... his six sisters Bridget, Rose, Catherine, Mary, Elinor and Ann [all of whom were married, but whose ages and married names are unknown]... Rev. Robert Harding minister of the Catholic Church of Phila. ... and a brother-in-law, Samuel Lewis. 
-The wording of the stipulations for the legacy of his wife and dau, if they should die include his sisters and preclude his having other children.
- Dau. Ann to have ½ of estate when age 20 (or earlier if married), unless his widow remarries in which case Ann gets 2/3 of the estate.
- Sisters to get 60 pounds, and more in case of death of widow and daughter.
- Brother in law Samuel Lewis to get 9 pounds annually for 3 years.
(Phila. Co. Will Book O:499, written and proved 1770.)

3. Mary Fitzimmons, widow of Phillip
1770-1774 Mary Fitzsimmons continues to live on Philip's 100 acres in Worcester Twp.
(PA. AR., Third Series, Vol. XIV.)
1774- Mary Fitzsimmons m. William Toy; and Ann Fitzsimmons, "infant dau. of Philip Fitzsimmons upwards of 14", chooses Henry Pawling Esq. as her guardian. 
(PA. AR., Vol. IX  ⁷ , "Marriage Records of Second Presbyterian Church, Philadelphia, 1774; Phila. Co. Court Docket Book 10:210. Before court Sept. 12, 1774: "Petition for Guardian", LDS Film #0021845.)
1779 - next extant list of Worcester Twp. : Mary Toy, widow
1788- Mary Toy, executor of Philip, sells to Samuel Baird [Bard?], Worcester Twp.
[Recorded 1789 as sold by assignee of Joseph Cauffman and Mary Toy, executors "Beginning stone in great Road...by Arnold Zimmerman. . .Stephen Boyers. . .John Adolph Mayer. . .Adam Vanfossen. . .by great road.]
(Mont. Co. Sheriff's Deed A-41, estate file  of Mary Toy; History of Worcester Township (ibid #1 above)

4. Estate Files of Mary Toy,  
Montgomery County Archives, Norristown PA,  Research of Barbara Wentz, 5 May, 2004
     RW17015 : 1800 Mary Toy, Providence Peter Skeen, Administrator
     OC19267: This file contains not only the records of Mary Toy, but also some records
      of Philip Fitzsimmons as they relate to her as late executor of his estate.
    1800 - Oct. 4^th, Inventory: Mary Toy, late of Providence, dated 6 Sep 1800, by Elisha Evans and James Skeen, [brother of Peter].
    1800 - Dec. 6^th Vendue Held, Peter Skeen, Administrator, purchasers: [list of only familiar names included] Samuel Bard...  Wm. Fitzgerald [wife "Eleanor" also a sister of Elizabeth Skeen?- wife of Joseph Skeen m. John Fitzgerald], James Skeen Jr [son of Peter]...  John and Jacob Fronefeldt...  Samuel Roberts... Peter Skeen... Valentine Shambaugh [Von Fossen/Skeen cousin]...  Andrew Casselbury...  Ann Newberry...  Elihu Trowbridge [husband of Mary and Peter Skeen's dau. Margaret- yellow silk gown, 3 petticoats, gold ring and silver spoon]...  Fred Turner [bought 11 times].
    1802 - Estate Settlement: Account of Peter Skeen, administrator of Mary Toy- Allowances to: Joseph Glover...Joseph Henry...Peter Turner for grave....William Fitzgerald...Henry Roosen Esq....Fred Baker...A. Webb...Derrick Casselberry...Elisha Evans...Owen Evans...Wm. Smith...Peter Skeen for funeral expenses...James Morgan Esq....Saml Skeen, crying Vendue...By cash paid Sarah Lewis pr settlement...By cash paid Ann Turner, her acct. for attendance during illness [this is probably Mary Toy's sister in law Ann or her dau. Ann?]...Peter Turner for Barn...Ann Wills per Rect....Seth Capman...A. Webb.

5. [Not in Estate Papers]
    1803 - Feb. 18, Joseph Cauffman, Ex, to the Estate of Philip Fitzsimmons, dec., is selling a Plantation in Providence, 4 miles above Norristown, on the Reading road, containing a log House, Barn, and Well.
    1803 - Dec. 30, Jonathan Meredith cautions people from buying the property of Philip Fitzsimmons, dec. being offered by Joseph Cauffman, because the premises have been mortgaged by Mary Toy, dec., in her lifetime, to Jonathan Meredith of the City of Phila. which has never been satisfied.
(Meier ²⁸ First Vol., pp. 18, 24.)

6. Estate File of Mary Toy
   OC19267
1805 - 14 May - Petition of Peter Skeen: That your petitioner administered the Estate of Mary Toy, dec. Petitioner has some time past settled his accounts as Adm., which have been confirmed by OC. Since which time real estate has been sold by Joseph Caufman, as surviving Exr. Of Philip Fitzsimmons  ­ which sale or part is said to belong to Estate of Mary Toy. Pet. requests to be released from his Adm in order that Register may appoint [Jonathan] Meredith or some other principal creditor of said Mary Toy who may have it in their Power to recover the said money from said Caufman for payment of their debts. Signed Peter Skeen.
1805 - 20 May - David Meredith, Administrator: We, David Meredith, Jonathan Meredith, William Meredith, all of Phila., bound to Pa for $600, Whereas Mary Toy, late Providence, died intestate and Adm. Granted to Peter Skeen, who entered upon Adm. by OC May Term 1805, leaving divers of the Goods, Chattels & Credits of said Mary Toy, unadministered. Conditions of obligation of David Meredith, Adm. Of Mary Toy, left unadministered by said Peter Skeen. . .make an inventory of Mary Toy, dec. left unadministered by Peter Skeen. . .that have or shall come to his hands, possession, or knowledge before 1 Dec next.  All three signed in presence of  J. Meredith ?? & Robert Morrison

7. Estate of Phillip Fitzsimmons is settled.  
1807 - Sept. 7: Subscribers hereby give notice to the Sisters of the late Philip Fitzsimmons of Worcester township. . . that a sum of money having been received by Joseph Cauffman, Ex. of . . . said Fitzsimmons, the devisees will be paid such proportions thereof as they are respectively entitled to, upon application to Margaret Cauffman, Ann Teresa Cauffman, Mark Wilcox, Executors of Joseph Cauffman
("Neighborhood News and Notices" from HSMC Bulletin Vol. 5, No. 4, p.333.)

NOTES:
(1)   Date of above is 37 years after will of Philip Fitzsimmons was proved!  
(2) The will of Joseph Cauffman Merchant of Philadelpia was proved Feb. 13, 1807.
(Mont. Co. Will Book 2:65.)
(3) The estate records of both Phillip Fitzsimmons and Joseph Cauffman in Philadelphia Archives have been checked by Rita Gerardine and neither of them mention the names of the heirs of Mary Toy.   An accounting in the file of Joseph Cauffman says only, "...paid to the heirs of Mary Toy".