While viewing Ken Burns's recent television documentary series on jazz, I was interested to see that Louis Armstrong had been hired as a teenage delivery boy by immigrant New Orleans coal merchants called Karnofsky. They took him under their wing, fed him a hot meal every evening, lent him five dollars to buy his first cornet. And because they were Jewish, as a gesture of gratitude for their generosity Armstrong wore a Star of David around his neck for the rest of his life. Thus they inadvertently contributed to American culture -- and earned at least a measure of immortality.

Aware that my grandfather's name had been Karnovsky before he abbreviated it, I reckoned that perhaps I could claim a connection to Armstrong and bask in the reflected glow of his glory. Like many immigrants, who sought to forget the hardships of the old country as they started afresh, my forebears seldom spoke of their past. But, prompted by curiosity, I decided to embark on a genealogical expedition, and I am now learning details about my lineage that I had never known. My guide on this voyage of discovery has been Jacob Karno, a retired Louisiana judge and a grandson of the Karnofskys who knew Armstrong. No sooner did I locate him than he concluded we belonged to the same clan, and, an energetic researcher, he has enlightened me with a wealth of information on my ancestry.

My grandfather, Bernhardt Karnovsky, arrived in New York in 1886, settled on the West Side and later in a leafy Brooklyn neighborhood, and sired 10 children. I inherited a faded photograph of him that depicts a slim figure with a handlebar mustache seated ramrod-straight and wearing a black suit and stiff celluloid collar. A cork cutter by trade, he soon Americanized his first name to Barnett and, out of admiration for Theodore Roosevelt, became a Republican precinct captain. Jacob's records indicate that Bernhardt and his wife, Rebecca, originated in Kovno, a town in Lithuania. Jews had resided there since the 16th century, and Jacob traced Karnovsky roots in the vicinity back to 1710 -- when our mutual patriarch Yankel, a tavern keeper, established the dynasty -- and determined that our great-great-grandfathers were brothers.

Jacob's computerized database contains 5,313 living and dead Karnovskys, with various versions of the name. They include the distinguished Shakespearean actor Morris Carnovsky and the Harvard biochemist Manfred Karnovsky. But Charlie Chaplin's impresario, Fred Karno, who popularized slapstick music hall routines like the custard pie in the face, is not among them.