According to legend the founder of the line (Stammherr), Sieghard de Rosis, came to Germany from Rome in 718 with St. Boniface.
According to this document, the knightly family of von Saldern was enfeoffed that year with tithe rights (mit den Zehnten) by St. Michael's Abbey near Nettlingen (Söhlde).
According to the book of fees (Fehdebuch) for the town of Brunswick, the lords of Saldern carried out raids in the surrounding area between 1379 and 1382.
The right-hand one is in memory of Matthias Friedrich von Saldern (born 22 April 1650; died 3 June 1680).
On 22 May 1406 troops under the Hildesheim bishop, John III of Hoya, Henry of Bortfeld and Burghard of Cramm, destroyed the walls of Gebhardshagen castle (today Salzgitter-Gebhardshagen) and captured it.
The ducal vassals, Jan and Burchhard von Saldern, were ordered to rebuild the armoury, the Red and the Grey Towers.
Around 1325, the counts of Wohldenberg enfeoffed the knights with the jurisdiction (Gerichtsbarkeit) of the village and the logging rights (Holzgrafschaft) on the Vorholz, a low, heavily forested ridge near Hildesheim.
That same year, however, Bishop John, dismissed the three sons of Heinrich von Saldern from the castle and Amt of Lauenstein.
In 1597, his son Burchard von Saldern (born 1568, died 29 December 1635), built the chapel in the castle courtyard.
In 1552, the Brandenburg prince-elector, Joachim II had the water castle of Plattenburg in the Prignitz transferred to his Keeper of the Privy Purse (Oberstkämmerer), Matthias von Saldern, as a bequest and fief.
Around 1570, Kurt von Saldern built Nettlingen castle and sold it around 1611 to the Brewers' Guild in Hildesheim.
In the 18th century, Caspar von Saldern was a civil servant and minister of state to Catharine II of Russia.
After 1990 his eldest son, Dietrich von Saldern, returned and founded a society with the aim of preserving the Plattenburg.
Karoline Albrecht, née Senfft von Pilsach, is the granddaughter of the last private owner and together with her husband they currently rent the castle.
The background to this donation was the fact that the Old Grammar School (Alte Lateinschule) west of the church was not able to cope with the rising number of students.