After her death in 1600, John William of Cleves took possession of these lands, but Maurice successfully defended his heritage in 1601.

The town of Uerdingen, incorporated into Krefeld in the 20th century, had been destroyed at the hands of troops from Hesse during the Thirty Years' War, and almost ceased to exist.

From 1607 Mennonites arrived in Krefeld, as in nearby Gronau, from neighboring Roman Catholic territories where they were persecuted.

In 1637, Op den Graeff was referred to as “the Mennonite lord Bishop” (der hiesigen Mennoniten Herrn Bischof) of Krefeld in the reformed community’s minutes book.

[9] They sought refuge in the lands of the more tolerant House of Orange-Nassau, at the time rulers of Krefeld; in 1657 their congregation was officially recognized and in 1693 they were allowed to build their own church, although hidden in a back yard (which still exists, reconstructed after World War II, with about 800 members).

Also the Quaker Evangelists received a sympathetic audience among the larger of the German-Mennonite congregations around Krefeld, Gronau, Emden and Altona, Hamburg.

They crossed the Atlantic on the ship Concord,[11] and founded the settlement of Germantown (now incorporated in Philadelphia), invited by William Penn, and thus beginning the Pennsylvania Dutch ethnic identity.

[13] In 1846 a Jewish representative was voted onto the town's municipal council, while rising antisemitism was noted during these elections.

The city of Krefeld itself operates four tramway and several bus lines under the umbrella of SWK MOBIL, a city-owned company.

Next to that the city plans to extend the line 044 in Krefeld-Hüls to connect the northern district of Hüls with the Krefeld downtown area.

[25] Since 1964,[26] the city has hosted an "honors program in foreign language (German) studies" for high school students from Indiana, United States.

The program annually places approximately thirty carefully selected high school juniors with families in and around Krefeld for intensive German language training.

[27] Since 1973, the fire services of Krefeld and twin city Leicester have played each other in an annual 'friendly' football match.