When I first started documenting family history, I asked my parents, aunts, and uncles what they could tell me, and what they remembered. My mother had a collection of funeral prayer cards, wedding invitations, and birth announcements, and these gave me a good start documenting family relationships, dates, and places.
The stories were even more interesting, as different people remembered different things, even sometimes about the same people and events. It made for interesting discussions. People told me what they knew and what they had heard. For example, everyone agreed that Martin and Anna Szczepański had six children.
They had been married in Szembruk, West Prussia, in November 1878, and they had immigrated to Buffalo, New York, in 1881. Their oldest son, Franciszek, was born in Buffalo in September 1884. I began to think that something was missing from this story, and I was right.
In going through the 1880 church registers from Szembruk, I found an entry for the birth and baptism of their first son, Józef, on 2 März 1880. 
Sadly, the last page of the available Szembruk records also had an entry for his death on 5 März 1880.
I did not find any other Szczepański children’s entries in the Szembruk records, but in the 1900 Bennington, New York census, Anna reported that she was the mother of nine children, and that five of them were still living.
Agnes would be born in Bennington, New York, on 2 August 1902.
Who were the three other children?
We know that after the death of their first child in March 1880, Marcin and Anna immigrated to the United States. Although I have not yet found record of their passage, Martin filed his first citizenship papers in Buffalo, New York, on 24 October 1881.
Since their other children were baptized at St. Stanislaus Roman Catholic parish in Buffalo, I re-examined the baptism records. They are now online at FamilySearch, and the Church has an index. There were several listings for Szczepański infants, and three of them were other children of Marcin and Anna.
Maria Szczepańska was born 17 June 1881 and baptized 19 June 1881.
On 2 October 1882, Marcin and Anna had Jan Szczepański, who was baptized 8 October 1882. I would have been surprised about the place listed as the parents’ place of birth, had I not known that Grudziądz is the county name and the name of the city near Szembruczek.
After the births of Franciszek (1884) and Marya (1887), Helena Szczepańska was born 16 Oct 1889 and baptized at St. Stanislaus in Buffalo 20 Oct 1889.
However, in the 1892 New York State census, only Frank and Mary were listed with their parents.
What happened to the other three little ones?
Sadly, St. Stanislaus Church also had records of their deaths and burial at St. Stanislaus Cemetery in Cheektowaga, New York.
Here is a timeline of the children of this family:
 Józef, pronounced YOO-zef, would have been his name in Polish, the language spoken by his parents. Because the Prussian government required even church records to be kept in German, his baptism record had the German/Latin name Joseph, pronounced YO-zef.
St. Stanislaus Bishop and Martyr RC Church, Buffalo, New York, Helena SZCZEPAŃSKI (Baptism), https://www.familysearch.org/ark:/61903/3:1:3Q9M-CS4N-64QB-Q
St. Stanislaus Bishop and Martyr RC Church, Buffalo, New York, Helena SZCZEPAŃSKI (Burial), https://www.familysearch.org/ark:/61903/3:1:3Q9M-CS4N-6498-B
St. Stanislaus Bishop and Martyr RC Church, Buffalo, New York, Jan SZCZEPAŃSKI (Baptism), https://www.familysearch.org/ark:/61903/3:1:3Q9M-CS4N-649N-N
St. Stanislaus Bishop and Martyr RC Church, Buffalo, New York, Jan SZCZEPAŃSKI (Burial), https://www.familysearch.org/ark:/61903/3:1:3Q9M-CS4N-649T-P
St. Stanislaus Bishop and Martyr RC Church, Buffalo, New York, Maria SZCZEPAŃSKA (Baptism), https://www.familysearch.org/ark:/61903/3:1:3Q9M-CS4N-649F-2
St. Stanislaus Bishop and Martyr RC Church, Buffalo, New York, Maria SZCZEPAŃSKA (Burial), https://www.familysearch.org/ark:/61903/3:1:3Q9M-CS4N-6439-9