There is a Wilhelm DIEHM buried at the Alsace Cemetery in Berks Co. Pennsylvania . .. and three other William DIEHMs also buried in other Berks Co.
The first site I noticed with our line mentioned (and my only knowledge of your George). They have not responded to my requests for source verification.I think their listing of the wife of Peter DIEHM as Catharine is incorrect - I believe it is Hanna Martha BOHN. http://www.tulpehockenroots.org/strauss/p000002t.htm#I3491http://www.tulpehockenroots.org/strauss/p000002t.htm#I3491
I inquired about this posting from the German Research Association, and found out the submitter (Warren K. Deem) is no longer living. I'm trying to contact some of his family. This is through another son of the John that I am descendant from. I believe Wilhelm's birth date is wrong here, but otherwise it is a match to my research: http://feefhs.org/gra/gralin20.htmlhttp://feefhs.org/gra/gralin20.html Diehm  William Rightmeyer (1837-1916) b Urbana, Champaign Co OH, wf McCord; John (1798-?) res Reading PA, wf Rightmeyer, Wilhelm (1778-?) res ? wf Kloos; Johann Peter (1729-1793) b Kembach-Wertheim, W?rt, wf Bohn 9/95
DIEHM, PETER, Reading. February 16, 1793 - April 3, 1793 (dates represent the date that the will was written and the date the will was proved) To wife Hanna Martha all real and personal estate during life. After her decease to son William my 2 out lots and £5 for his birthright. To sons John and Frederick my dwelling house in Reading also 2 lots in same town. To dau. Catharina £8. Remainder to 3 sons above named. Exr: Brother-in-law Frederick BOHN. Wits: John GOODHART and George YOUNG.
KLOOS, JOHN, Alsace. January 22, 1794 - October 13, 1795. (dates represent the date that the will was written and the date the will was proved) Mentions having sold the plantation to son Jacob for £400. Provides for wife Maria Barbara. To my 5 daus., Maria Elisabeth wife of Abraham SCHNEIDER, Maria Barbara wife of John Adam SPENGLER, Maria Christina wife of Conrad SHEPP, Maria Catharine wife of William DIEHM, and Maria Magdalena KLOSS £80 each which Jacob is to pay. Exrs: Son Jacob and brother Henry KLOSS. Wits: John SPAYD and Daniel ZACHARIAS, Jr.
These are some other possible clues about Johann/John Peter DIEHM with various spellings of the name - even transcriptions of the same ship records seem to have butchered the same name several ways. It's difficult because there appears to have been several Germans with similar names who immigrated from the same region of Germany to Pennsylvania around the same time . . . and then the Berks Co. Church records list a John Peter Diehm's birth Feb 20 1729 in Pennsylvania, so hard to say which of these are ours.
ancestry.com Pennsylvania Church Records - Adams, Berks, and Lancaster Counties, 1729-1881 about John Peter Diehm Name:John Peter Diehm Date:20 Feb 1729 Event:Birth Relation:Born Location:Berks CO., PA Church:Schwartzwald Reformed Church Record_ID:265057
ancestry.com Name:John Peter Diehm Date:4 Mar 1793 Event:Burial Relation:Decedent Location:Berks CO., PA Church:Schwartzwald Reformed Church Record_ID:265057
ancestry.com Names of Berks Countians Who Were Naturalized in the Province of Pennsylvania, 1760-1762 Peter Diehm, Sacrament taken 12 September 1762
ancestry.com Pennsylvania Census, 1772-1890 about Johan Peter Diehm Name:Johan Peter Diehm State:PA County:Philadelphia County Township:Philidelphia Year:1753 Database:PA Early Census Index
ancestry.com Passenger and Immigration Lists Index, 1500s-1900s about Johann Peter Dihm Name: Johann Peter Dihm Year: 1753 Place: Pennsylvania Source Publication Code: 4525 Primary Immigrant: Dihm, Johann Peter Annotation: Date of emigration and intended destination or date and port of arrival. Extracted from manuscripts in the princely archive of Lowenstein-Wertheim-Rosenberg. Also in source nos. 4517 and 9964 (indexed in PILI 1991 and 1983, respectively).Source Bibliography: LANGGUTH, OTTO. "Pennsylvania German Pioneers from the County of Wertheim." Translated and edited by Don Yoder. In The Pennsylvania German Folklore Society [Yearbook], vol. 12 (1947), pp. 196-289. Page: 207