If we are stuck trying to find the origin and dates of ancestor William Tilson, but then discover the man served in the American Revolution, the obvious next research option is to see whether he is listed as a Patriot at the D.A.R. website.
Sure enough, William did have a listing on the D.A.R. website—with the minor revision of an additional "l" tacked on to his surname. The D.A.R. entry showed William Tillson born in Plymouth County, Massachusetts, in 1741, the same year as the Tilson Genealogy had told us.
According to the D.A.R. file, William was listed as having provided "patriotic service" in Virginia by paying a "supply tax" in 1783. The source of that information was listed as having come from a microfilm at the Library of Virginia regarding Washington County personal property taxes. (Fortunately, that same collection is currently available through FamilySearch.org.)
There was a long list of D.A.R. members who had applied for membership on account of their descent from William Tillson. The D.A.R. website sorted the listings according to the specific child of William Tillson whom each member claimed as ancestor. Included in that long list were a few descendants of Peleg, William's son whom I also claim as my fourth great-grandfather.
As I looked over the D.A.R. list, I realized that one of the descendants of Peleg Tilson was a third cousin whom I had met online during the early days of genealogy forums. Since it is possible to purchase a copy of the application and supporting documentation (with information on living people redacted), I decided to take a look at her file.
Thankfully, the purchased file walked me through document after document tracing the way from this distant cousin back through several generations. All the documents you would expect were either copied onto the file or cited in the application. Census records, obituaries, marriage licenses—all the expected paperwork, including copies of family Bible entries—walked me back, generation by generation, until the point of Peleg's daughter Rachel's marriage to James Davis. And then, the litany of records stopped.
Of course, I had most of those records already copied into my own tree. After all, those are the types of documents which we all appreciate finding at Ancestry.com or FamilySearch.org. Digitized documents rock. But what about the details beyond that point? That's what I was purchasing the D.A.R. file to find.
There were other resources listed, of course. Just not what I had hoped for. Handwritten notes, most likely added by a local D.A.R. registrar, named two books as resources to guide those making a membership decision. One of the books was a 1981 publication by Pat Alderman called Tilson Grist Mill. The other was a reference book which has become stock in trade for those of us researching our Tilson roots: Mercer Vernon Tilson's The Tilson Genealogy.
Nothing ventured, nothing gained, I suppose. But I had hoped for more guidance on just how writers like Mercer Vernon Tilson had pieced together the story on this family line. After all, his claim is that William Tilson can trace his heritage back to some of the travelers on the Mayflower. Depending on how strict the Mayflower folks are regarding documentation for membership in their organization, pointing to a book—even a book published over one hundred years ago—may not be enough to satisfy.