This is certainly not a common area name and I found few mentions of it. If you haven't already, you may want to go to the Chester County rootsweb site, mentioned in your Welcome Email, and look through all the tax records that are there.....you might get lucky. I looked in THE HISTORY OF CHESTER COUNTY PA, by futhey and Cope, but there is no mention of the surname, any spelling. I also looked in the 1765 Chester archives, with no luck. I found this will which has no mention of whom you seek...it is the Del. Co probate records. There are no other area wills for a Wm Siddon, any spelling....this includes Chester, Del, Lanc, Bucks, Berks, Philadelphia, and others, SIDDONS, WILLIAM, Chester.May 12, 1815 - June 28, 1820.Wife ____; children: John, Sarah, Ann and Joshua.Exrs: Sd. wife.Wits: William GRAHAM and Samuel J. WITHY. #533. This is from CHESTER AND ITS VICINITY DELAWARE CO IN pa....by John Hill Martin, esq; "at Munday's Run near Chester town, Old Siddons knocked the pedler down, and robbed him of his golden store and left him in the weltering gore. In reality, Siddons was captured, taken to Chester and tried. He was acquitted and died in 1824, buried in the old grave yard of St Paul's. It was said that the pedler's ghost was often seen in the dusk of early twilight walking about the "widow McIlvain's Meadow." also found this.....same book.....".......house at the S.E. corner of Second and Edgmont, known as the Siddon's house." same book; .....Wm Siddons and John Wood occupied pew 2, 1803, St. Pauls Sandra