How to find out if your grandfather is just... (shall I say it?) ...blowing his own horn...

My grandfather, William F. Robie -- known to his grandchildren as "Pop," was a great storyteller and had a prodigious memory for the past.  Like many good storytellers, though, he never let the truth get in the way of a good yarn!  So I learned over the years to take his tales with a grain of salt, and never more so than when he was being serious.  He used to tell me about his parents' early married life in SE Washington, DC, saying that they were neighbors and friends of the great composer and band leader, John Philip Sousa, and the two families would get together frequently for visits and meals.  Yeah, right.  Living in the same neighborhood with a famous person doesn't necessarily make you best friends.

William Robie, father of William F. Robie
John Philip Sousa

Wikipedia states that John Philip Sousa was resident in DC until 1892, when he resigned from the U.S. Marine Band and began touring with his own band.  The Robie's married in 1891, which didn't leave a lot of time for them to hang out with the Sousa's before he left town.  So in this case, I was fairly skeptical of Pop's story.
Good genealogical practice involves researching not just your ancestral line, but those of your ancestor's brothers, sisters, aunts, uncles, and associates.  Here's what I found:
The Robie's lived near John Philip Sousa in DC
  • In 1890 and 1892, "William Robey" was listed as residing at 517-7th SE, occupation:  police (1890, 1892 Boyd's Directory of the District of Columbia)
  • In 1890, Zebulon Rhodes resided at 223-12th St. SE (1890 Boyd's Directory of the District of Columbia)
  • William Robie married Mabel Clyde Rhodes in Washington, DC in July, 1891 (no date provided in record, microfilmed marriage index viewed at the Marriage Bureau, DC Courthouse)
  • In 1899, Zebulon Rhodes stated that he was the father of Mabel C. Robie and that her mother, Sarah Ellen Grimes, had died on 2 February 1878. (Zebulon Rhodes affidafit dated 1 September 1899, civil war pension file, National Archives.)
  • John Philip Sousa's birthplace is 363 G St., SE, Washington, DC. (John Philip Sousa, American Phenomenon by Paul E. Bierley, viewed online via Google books)
  • In 1887, John Philip Sousa lived at 204 6th St. SE (1887 Boyd's Directory of the District of Columbia)
  • In 1892, John Philip Sousa lived at 313 B St. SE( 1892 Boyd's Directory of the District of Columbia)
  • In 1887 and 1892, Antonio Sousa, brother of J.P. Sousa, lived at 500-7th SE (1887,1892 Boyd's Directory of the District of Columbia)
  • The Navy Yard, home of the Marine Band, is located in SE Washington.
The Robie's were friends with John Philip Sousa
  • Sarah E. Grimes, the mother of Mabel Robie, was the daughter of Henry V. Grimes and his wife, Catherine H. Lindsey.  (1850 federal census; administration of estate for Catherine H. Grimes,1868; DC marriage index; notes copied from Sarah Grimes' bible, present whereabouts unknown)
  • Henry V. Grimes and Catherine had the following children who lived to adulthood: Samuel J., Alfred, Mary Susan, Sarah Ellen, Cinderella, and Margaret.  By 1880, only Cinderella and Mary were still living.  (administration of estates for Samuel J Grimes, 1867 and Catherine H. Grimes, 1868; will of Margaret Grimes, 1868; Rhodes affidafit, civil war pension file)
  • In the process of researching all the siblings of Sarah E. Grimes, I discovered that her sister, Mary Susan Grimes, married Henry R. Cohill on 26 August 1858, (DC marriage index) 
  • The children of Mary S.Grimes and Henry Cohill listed in the 1860,1870, and 1880 census included:  Cora V., b. 1859, Bion N., b. 1862,  Ada L., b. 1867, and Candace, b. 1872
  • Mary S. Cohill was a widowed head of household in the 1900 census, residing at 619 G St. SE.  Included in her 1900 household were her daughter, Candace Sousa and her son-in-law, Antonio Sousa.   According to the census data, Candace was born in December of 1871, had been married 5 years (marriage date ca. 1895), and the mother of three children, all of whom were still living in 1900.  Candace was born in DC, as were both her parents.  
  • Antonio Sousa was the younger brother of John Philip Sousa.  According to the Bierley biography, he was the ninth child in the Sousa family, born in DC on March 25, 1868.  "He was at one time a letter carrier and post office clerk.  He also contributed to the sports columns of the Washington papers, wrote verse, and collaborated with Edward Lewelly on an opera. He died on 8 May 1918 in Rocky Ford, Colorado, where he had been sent to recuperate from tuberculosis, and was buried in the Sousa plot in Congressional Cemetery."(Bierley biography of Sousa, Congressional cemetery online database)

Since we know that John Philip Sousa left town in 1892, the "partying with the Robie's" pretty much had to end that year.  I created a map to plot the locations of where the individuals I've mentioned actually lived.

View ancestral southeast d.c. in a larger map

Immediately, I saw that in 1890 and 1892 William Robie lived just a few doors away from the Sousa family home on 7th Street, SE -- the head of household at that address in the 1880 census was Elisabeth Sousa, John Philip and Antonio's mother; several of her children remained at home, including Antonio but not John Philip.  In addition, Antonio Sousa continued to be listed at this address In the 1887 and 1892 DC city directories (used to provide information lost in the destroyed 1890 federal census).  Everyone else in the story certainly lived in SE Washington, but as I said before, just living in the same part of town isn't the same thing as being friends, or even acquaintances!  

Furthermore, the marriage of Mable Rhodes' cousin Candace Cohill to Antonio Sousa didn't take place until approximately 1895, by which time the Robie's had moved down to the Robie family farm in Charles County, Maryland, so it is not likely that Mabel's distant connection  with the Sousa family was the cause of this purported friendship, if it actually existed.  
So, in the absence of a Sousa diary or manuscript mentioning his good friend Bill Robie, it would be pure conjecture to reach any conclusion about the nature of the social interaction between my ancestors and the Sousa family.  But the fact that William Robie was a neighbor of theirs implies that he might certainly have at least met the famous band leader.  
The discovery of a marriage between my ancestor's cousin and a brother of John Philip Sousa initially led me to believe that there might be some substance to Pop's story, but the fact that the marriage occurred after the time period in which William Robie and members of the Sousa family were in the same vicinity lends credence to a different hypothesis -- in which Candace Cohill and Antonio Sousa actually came together through their separate relationships with Bill Robie:  Antonio as his neighbor, and Candace as the cousin of his wife, Mabel.
More research remains to be done on this question to nail down exact dates, and look for manuscript sources on Sousa.  The 7th street neighborhood was also the location of Trinity Church, Washington's oldest Episcopalian parish.  It is certainly possible that everyone met at church, although perhaps less likely in the case of William Robie.... (I'll write more about that another time!)  Next visit to Washington, I plan on fleshing this out some more; even better, if any cousins reading this have better data, please let me know.  In any case, a fun exercise!