Of the seven children in Beethoven's family, only three boys survived.

Ludwig, the eldest, became the talented composer whom we know. He felt himself responsible for his brothers, even when they became adults and married. Even so, in 1795, the two men rejoined Beethoven in Vienna all the same...  

Kaspar Anton Karl (often named Karl, like his son) was the closest of the two brothers to Beethoven. After having tried his hand at music, following in his brother's footsteps, he worked as a clerk in the Department of Finance. He died of consumption and left his son, Karl, under the joint guardianship of his wife and Ludwig. Kaspar was the only member of Beethoven’s family in this generation to have a child.  

Nikolaus Johann (generally known as Johann) became first of all an apothocary, but later declared himself as a 'land-owner' (to which his composer brother retorted that in this case he himself was a 'brain-owner'!).

Many men in those days chose fishing as their trade. They would spend their days fishing with catfish lures and bait. Catfish were plentiful in the local lakes and the men could also design lures for extra income. Members of the Beethoven family were better schooled and consequently had more opportunities open to them.

Ludwig Maria van BEETHOVEN

Baptised April 2nd 1769 at Bonn
Died April 6th 1769 at Bonn.

Ludwig van BEETHOVEN

Baptised December 17th 1770 at Bonn
Died March 26th 1827 at Vienna.

No children

Kaspar Anton Karl van BEETHOVEN

Baptised April 8th 1774 at Bonn
Died November 15th 1815 at Vienna

Married May 25th 1806 at Vienna
to Johanna REISS (1786-1868)

Son: Karl van BEETHOVEN
Born September 4th 1806 at Vienna
Died April 13th 1858 at Vienna

Married July 16th 1832 at Vienna
to Karoline Barbara NASKE

5 children...

Nicolas Johann van BEETHOVEN

Baptised October 2nd 1776 at Bonn

Died January 12th 1848 at Vienna

Married November 8th 1812 at Linz

to Thérèse OBERMAYER (1787-1828)

No children

Anna Maria Francisca van BEETHOVEN

Baptised February 23rd 1779 at Bonn

Died February 27th 1779 at Bonn

Franz Georg van BEETHOVEN

Baptised January 17th 1781 at Bonn

Died August 16th 1783 at Bonn

Maria Margarita Josepha van BEETHOVEN

Baptised May 5th 1786 at Bonn

Died November 26th 1787 at Bonn

Karl van Beethoven marries Karoline Barbara Naske on July 16th 1832. He is 26 years old and is a second lieutenant. She is 24.

They are to have five children, the only descendants of this branch of Beethoven's family, of which there is only one boy, who immigrates to the USA (under, it would seem, the name of Louis von Hoven).

The children of Karl and Karoline are to have, between them, 20 children. There will be 13 in the next generation and very few after that...

Karoline Johanna van BEETHOVEN

Baptised November 5th 1831 at Vienna

Died August 30th 1919 at Vienna

Married November 25th 1854 at Vienna

to Franz de Paula Carolus Magnus WEIDINGER (1823-1882, brother of Paul ErnstVinzenz Ignaz)

Eight children: six boys and two girls

- Franz Karl Josef WEIDINGER (1855-1932)

married Hermine SCHALL (Vienna 1881)

they are to have three boys and a girl...

- Karl Eduard Paul WEIDINGER (1856-1930)

married Leopoldine Elisabeth JANSEN (Vienna 1882) then Josefa KUNET (Vienna 1922)

they will have two girls...

- Paul Adolf Robert WEIDINGER (1858-1940)

married Sidona Ludowika UHER (Vienna 1882)

they will have a girl and a boy...

- Eugenie Karoline WEIDINGER (1859-1893)

single and without descendants

- Gustav WEIDINGER (1862-1944)

married Julie Emma Wilhelmine RITTNER (Vienna 1895)

they will have one girl and then two boys...

- Karoline Johanna WEIDINGER (1863-1865).

- Robert Franz Karl WEIDINGER (1865-1920)

single and without descendants

- Hugo Robert Paul WEIDINGER (1866-1894)

married Karoline Justina Maria WEBER (Vienna 1894)

No descendants

Marie Anna van BEETHOVEN

Baptised August 31st 1835 at Niklowitz

Died September 29th 1891 at Vienne

Married February 23rd 1857 at Vienne

to Paul Ernst Vinzenz Ignaz WEIDINGER (1828-1904, brother of Franz de Paula Carolus Magnus)

Three children: two girls and one boy

- Marie Josefine WEIDINGER (1859-1936)

single and without descendants

- Hermann Franz Karl WEIDINGER ( 1861-1932)

married Marie Caroline TOTZ (Vienna 1892)

they will have one girl (who in turn has two children)...

- Helene WEIDINGER (1863-1863).

Ludwig Johann van BEETHOVEN

Baptised March 31st 1839 at Vienna

Died between 1890 and 1916, in France or Belgium

Married February 27th 1865 at Vienna

to Maria Anna Philippina NITSCHE (1846-1917)

Six children: the family emigrated to the USA around 1871 (under the name Louis von Hoven):

- Marie van BEETHOVEN (1865-1865).

- Karl Julius Maria van BEETHOVEN (1870-1917)

single and without descendants

- Heinrich van BEETHOVEN (1871-1872), in the USA.

- Meta van BEETHOVEN (1874- before 1890), in the USA.

- and two other children, perhaps the only ones who still carry the name van BEETHOVEN and descend from Ludwig's brother?

Gabriele van BEETHOVEN

Baptised March 24th 1844 at Vienna

Died October 10th 1914 at Vienna

Married May 14th 1864 at Vienna

to Robert Franz HEIMLER (1833-1910)

Two children: one boy and one girl

- Gabriele Maria Ludowika HEIMLER (1865-1903)

married Emil ZIMMERMANN (Vienna 1891)

they will have a girl...

- Raoul HEIMLER (1876-1948)

married Alice Maria Nora STERN (Vienna 1913)

no descendants

Hermine van BEETHOVEN

Baptised July 31st 1852 at Vienna

Died April 7th 1887 at Vienna

Married July 18th 1876 at Vienna

to Emil AXMANN (1850-1935)

One boy:

- Egon AXMANN (1886-1926)

single and without descendants

Source: Beethoven, die Geschichte seiner Familie, Joseph Schmidt-Görg