Sara Borchardt, 1817 Koslin -1865 Berlin, wife of Anton Nathusius, was descended from a line of Borchardts that is known back to the early 17th century in Halberstadt.

Hannah Burchcadt, daughter of Naphtali Hertz ben Baruch Burchcadt and Jeremias Jacob of Halberstadt, was born circa 1665 and married Philip Lipmann (1638-1691).

Their son, born 1670 in Halberstadt, died 1750 in Koeslin, was Philipp Borchardt (Baruch ben Lipmann). With his wife, Edel Yomtob (b. 1675 Eger, Hungary d. 21.6.1769 Halberstadt), they had nine children:

1. David
2. Johanna
3. Joachim: b 1711 Koeslin, 4 children
4. Isaak Richard: b 1710 Koeslin, d. 1790 Halberstadt. Married Schoenchen Levi - three children
5. Salomon Meschullam (Scholum Koeslin): b.1718 Koeslin d. 1783 Jastrow (Jastrowie). Married Rebecca Moses - seven children.
6. Berend: b.1695
7. Samuel
8. Jacob: b. 1698 d.1742
9. Herz: b.1712 d.1776
   

Salomon (Meschullam) Borchardt and his wife Rebecca children were:

1. Judith (Juetel): b 1747 Koeslin
2. Hindel: b. 1749 Koeslin d. 29.11.1817 Berlin. Married Salomon Jacob 18.8.1765 - one son, Itzig Salomon Jacob (1770-1847)
3. Jacob Salomon (Carl Bernhard Siegmund) b. 3.12.1753 Koeslin, chr. 1798, d. 16.4.1835 Koeslin. Married Taubchen Lewy (Abraham) Berlin 1783. Three children: Rebecca, Moritz and Sara.
4. Philip Salomon: b. 1742 Koeslin, d. 1833 Koeslin. Married Rebecka Itzig 28.5.1760 Berlin. Described as 'anges auf Grund de Gen Priv des Daniel Itzig.'Four children: Moses Philipp (b.1762 d.Exin, Pommern), Baruch Philipp, Isaac Philipp (b.1780 Koeslin d. 19.4.1824 Sclawe, Pommern), and Salomon Philipp (b.1765 Koeslin d.Czarnikau/Czarnkow).
5. Rebecca: b. 1.11.1777 d. 11.12.1833 Berlin. Married 1. Veital Bernard Friedlander - three children - 2. Elkan Flesch.
6. Isaac Salomon: b. 2.7.1743 Koeslin, d.1.5.1818. Married Hanna Liebmann 13.8.1770 Koeslin. Four children: Wolf Isaac, Salomon Isaac, Abraham Isaac and Benedict (Bendix) Isaac.
7. Frommeth: b.1745 Koeslin.

Sarah's father, Baruch Philipp (b 1767 Koeslin d 1836 Koeslin), son of Philipp Salomon,  is described in 1817 as 'tuch und schittelwaren handler anges auf Recht des B Bankiers Daniel Itzig.' He had married Jette Abraham (Gretschen) Benda (Gute) in 1806 in Koeslin.

They had three daughters:

1. Johanna (b. 24.12.1813 Koeslin d. 2.7.1892 Berlin) married 30.9.1835 Dr David Davidson: they had 4 children: Elise, Auguste, Antonie and Otto.
   
2. Laura (b. 10.10.1817) who married Kanitz: 5 children - Clara, Johannes, Martha, Elizabeth and Anna.
3. Sara (1.7.1809 Koeslin d.10.10.1865 Berlin) Anton Nathusius by whom they had 5 children.