Ernst Friedrich, who had a strict Lutheran upbringing, started a reconciliation between Lutheranism and Calvinism with the publication of the Staffort Book in 1599 His occupation of Upper Baden caused serious conflicts – even with the Emperor – the consequences of which damaged Lower Baden and ultimately also led to losses of territory.

Ernest Frederick was the eldest son of the Margrave Charles II of Baden-Durlach and Anna of Veldenz.

Charles II's last will and testament forbade that, but it had not been signed and sealed, so the remaining guardians decided to give them their way and divide the country.

Ernest Frederick received Lower Baden, including the large towns of Durlach and Pforzheim.

[1] His younger brothers James and George Frederick also received parts of the country, so that the land was further divided beyond the existing division into Baden-Durlach, Baden-Baden.