This is WORK IN PROGRESS and is written to the best of my knowledge at the present time, so it may NOT be correct as details are sparse. PLEASE DO NOT use this as truth, copy it or post it on Ancestry or other sites.

Matthias Rapp was born April 7, 1795 in Kehl, Germany. His father was Michael Rapp (1760-1840). His mother was Magdalena Lapp (1770-1835).

Matthias was a mason. He married Anna Barbara Walther (1798-1821) on April 27, 1817 in Kork u. Muckenschopf, Baden, Germany.

Daughter, Elizabeth Rapp, was born January 1, 1819 and baptized January 14, 1819 in Kork, PreuBen, Baden at Querbach Parish.
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Baden, Germany, Lutheran Baptisms, Marriages, and Burials, 1783-1875
Name: Matthias Rapp
Gender: männlich (Male)
Marriage Age: 22
Event Type: Heirat (Marriage)
Birth Date. abt 1795
Marriage Date: 27 Apr 1817
Marriage Place: Kork u. Muckenschopf (Kork), Baden (Baden-Württemberg), Deutschland (Germany)
Father: Michael Rappen
Mother: Magdalena Rappen
Spouse: Anna Barbara Waltherin
Parish as it Appears: Kehl
City or District: Kork u Muckenschopf
Author: Evangelische Kirche Muckenschopf (A. Kehl)

Baden and Hesse Germany, Lutheran Baptisms, Marriages, and Burials, 1502-1985
Name: Mathias Rapp
Gender: männlich (Male)
Marriage Age: 22
Event Type: Heirat (Marriage)
Birth Date: abt 1795
Marriage Date: 27 Apr 1817
Marriage Place: Kork, Baden (Baden-Württemberg), Preußen
Father: Michael Rappen
Mother: Magdalena Rappen
Spouse: Anna Barbara Waltherin
Parish as it Appears: Neumühl
Page number: 11

Source: Ancestry.com Family Trees (accuracy not guaranteed, and I find no verification for these except Jacob.)
Name: Matthias Rapp
Birth: 7 Apr 1795 - Kehl, Ortenaukreis, Baden-Wuerttemberg, Germany
Death: Jan 1860 - Richfield Township, Henry County, Ohio
Father: Michael Rapp (1760-1840)
Mother: Magdalena Lapp (1770-1835)

Grandfather: Georg Michael Rapp Sr. (1739–____); Kehl, Baden, Germany ?
Grandmother: Christina ?

Father: Michael Rapp Jr. (1760-1840); b. and d. Kehl, Baden, Germany
Mother: Magdalena Lapp 1770-1835; b. and d. Neumeuhl (Kehl), Baden, Germany
Children of Michael and Magdalena (Matthias' siblings)
Michael Rapp 1791-1812
Johannes Rapp 1792-1859 ((b. Baden, Wurttemberg, Germany)
Mathias Rapp 1795-1860
Andreas Rapp 1797-1797 (b. and d. Neumuhl, Baden, Germany)
Magdalena Rapp 1800-1883
David Rapp 1802-1877 ((b. Neumuhl, Baden, Germany)
Jacob Rapp 1804-1875 (b. Baden, Niedersachsen, Germany)
Barbara Rapp 1809-1810
Elisabeth Rapp 1811-1893 ((b. Neumuhl, Baden, Germany)

Spouse: Anna Barbara Walther (1798-1821); Married 1817
Children:
Anna Barbara (1817-1831)
Elizabeth (1819-)
Jakob (1820-1897)
Magdalena (1821-1821)
Spouse: Elisabeth Scheer (1793-); Married 1822
Children:
Michael (1822-1849)
Anna Maria (1826-)
Margaretha (1827-)
Magdalena (1828-1885)
Katharine (1829-1906)
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If this is the correct Matthias Rapp, then this was his will:

Ohio, U.S., Wills and Probate Records, 1786-1998
Name: Matthias Rapp
Residence Date: Abt 1860
Residence Place: Henry, Ohio
Probate Date: 3 Feb 1860
Probate Place: Henry, Ohio, USA
Inferred Death Date: 1860
Inferred Death Place: Ohio, USA
Item Description: Will Records, Vol 1-3, 1852-1886
Others Listed:
Matthias Rapp
Barbara Markloff - Daughter
George Markloff - Son-in-law
Jacob Burringer – Executor

Record of Matthias Rapp's Will
Be it Remembered that at a Probate Court held within and for the County of Henry and State of Ohio at Napoleon on the third day of February in the year of Our Lord one thousand eight hundred and sixty before Thomas S. C. Morrison Judge of said Court, the following proceedings were had:
In the Matter of the Last Will and Testament of Matthias Rapp, Deceased [Probate of Will February 3rd, 1860]
The last Will and Testament of Matthias Rapp, late of the Township of Richfield in said County, deceased, was this day produced in Court by Jacob Burringer, the Executor in said Will, named and David Swarts, John J. Bollmer and John J. Bollmer Jr., the subscribing witnesses to said will, appeared, and in open court on oath testified to the due execution of said will; which testimony was reduced to writing and by there respectively subscribed, and filed with said will; and it appearing to the Court, by said testimony that said will was duly attested and executed, and that said Testator, at the time of executing, the same, was of full age, and of sound mind and memory, ad not under any restraint, It is ordered by the Court, that said Will be admitted to Probate, and with the testimony be recorded. Thereupon, Jacob Burringer, the Executor, in said Will named, appeared in Court and signified his acceptance of the trust of executing said Will. It is therefore further ordered that letters of Testamentary be issued to him on his giving bond in the sum of Two Hundred Dollars with John J. Bollmer Jr. and David Swarts as soneties (?) conditioned according to law. The Court appoint John J. Bollmer, Sr. and John J. Bollmer Jr. and David Macklin appraisers of the personal estate of said Testator.
Attest: T. S. C. Morrison, Probate Judge

Matthias Rapp's Will
This tenth day of January of Our Lord one thousand eight hundred and sixty [January 10th, 1860], in the name of God, Amen: This is my last will and testament from me, Matthias Rapp with sound intellect endowed thanks God, but weak in my body; that my daughter Barbara, married to George Markloff, and her heirs Administrators and Executors, my property after all my honest and just debts are paid, shall keep and possess as her property as long as she lives after my death, and shall it be the case that she my daughter should die before her husband and have no living children, so shall after her death this her property be granted to George Markloff for his use and possession so long as said George Markloff will live, but shall have no right to sell this her property, and after his death shall when no children or heirs from my daughter are alive; the said property shall fall back to my nearest relations; this aforenamed property containing forty acres of land which is the southwest quarter of the southwest quarter of Section twelve township four north of Range Eight East (SW ¼ of SW ¼ of Sec. 12 T.4 North of R. 8 East) containing forth acres more or less in Henry County and State of Ohio.

I therefore appoint Jacob Bussinger for me as Executor. Done this tenth day of January 1860 in Richfield Township, Henry County, Ohio.
Matthias Rapp
Done in presence of John J. Bollmer Jr., David Swarts, John Bollmer
The State of Ohio, Henry County
We, David Swarts, John Bollmer and John J. Bollmer Jr. being duly sworn in open Court this 3rd day of February A.D. one thousand eight hundred and sixty, depose and say that we were present at the execution of the last Will and Testament of Matthias Rapp, deceased, hereunto annexed; that we saw the said testator, subscribe said Will and heard him publish and declare the same to be his last will and testament, and that the said testator, at the time of executing the same, was of full age, of sound mind and memory, and not under any restraint, and that we signed the same as witnesses at his request, and in his presence, and in the presence of each other.
Sworn to and subscribed before me in open Court this 3rd day of February 1860.
T. S. C. Morrison, Prob. Judge
The State of Ohio, Henry County
I, Thos. S. C. Morrison, Judge of the Probate Court within and for said County, do hereby certify the foregoing to be a true and complete Record of the last Will and Testament Matthias Rapp, Deceased, together with the testimony and order admitting the same to Probate.
Attest: T. S. C. Morrison, Probate Judge