The castle of the Counts of Champagne was built from the 11th to the 12th century. It was demolished in 1805 in order to widen the canal. It was a fortress, arsenal and prison. The Counts of Champagne were great lords with as much power as the King of France. Champagne was not yet part of the royal domain and was only attached to France in 1284 following the marriage of Philip the Fair with Jeanne, daughter of a Count of Champagne. In 1040, Rachi was born and France was under a feudal regime. Under the authority of the Counts, the Jews lived on the whole in an atmosphere of relative tranquility.
Jewish communities did not stop growing in Troyes during the 11th century and under the reign of Count Thibaud. There were between one hundred and one hundred and fifty Jews out of four thousand inhabitants.