Jean Corneille De Boom – later known as John Cornelius, or simply Cornelius, was born on June 13, 1818 in Denderlieu., Belgium. To see a copy of his birth certificate, click on 10_Cornelius_Birth_Certificate which was issued in Anvers (Antwerp).
According to an Ancestry.com entry (now deleted) “Marie Badarous was “married to Jean Corneille De Boom on 17 Mar 1856 in San Francisco, San Francisco Co, CA. Marie Marguerite Badarous was born about 1838 in Paris, Paris, France. She died in San Jose, Santa Clara Co.” However, Yannick Le Gall’s family tree posted on Geneanet adds “Marie Marguerite Badarous was born 21 December 1836 in Paris 75, Ille de France, France and died sometime in February(?) 1899 in San Jose.”
Cornelius and Marie had no children, so he appointed his nephew Romain Camille DeBoom (Emma’s father) his executor and heir. (according to RC’s letter to the Society of Pioneers who had requested information about Cornelius). Their European relatives contested the will, and the landmark case went up to the California Supreme Court. (See the Estate Debate page.)
Return to Europe
“In June 1864 Cornelius De Boom left San Francisco for Europe, where his mother could not live any longer without seeing him again. After her death, he made two more Business visits here, but he kept his Country Residence near Paris.” [source 211_RC DeBoom letter 19May1911]
Cornelius was 52 when he died in Paris on September 21, 1870 according to his Death Notice (11_Cornelius_Death_Notice). The Siege of Paris during the Franco-Prussian War of 1870 had begun just two days before when the Prussians encircled the city. This blockade explains why the Death Notice indicates his body will be kept in Paris “until events permit” at which time he will be buried in Denderleeuw, Belgium, the De Boom family home.
We know Cornelius died of smallpox from a translated 1937 Letter to Emma from Angelique de Larencel, her cousin, the Baroness de Poliniere. Angelique remembers her uncle (the “brother of my mother”) visiting in Paris when she was a small child. “He brought us candies and he is the one who died of smallpox during the war of 1870-1871.” Later she adds,” How much I wish to know you! And how I hope that you would be able to come and visit the land of your ancestors. But at the present time our poor Europe is in turmoil, and peace quite threatened.” Hitler invaded Paris only three years later. If you read French, see the original letter at
The Napa Daily Register of August 27, 1885 published a summary of his life based on an interview with R.C. De Boom, then living in Napa.