His heir was his brother Alexander who was incapable of ruling on account of a mental illness so a regency had to be established.

[1] In the first scene (1895–97) of the Lippe succession dispute, it was claimed on part of the Schaumburg-Lippe that count Ernest's paternal grandmother, noblewoman Modeste Dorothea Christiane von Unruh (1781-1854) (who belonged to a family of lower nobility) was not of high enough birth to be legitimately a dynastic wife - that would have made progeny born of her ineligible to succeed.

[citation needed] A settlement was reached in 1897 when a commission under the presidency of King Albert of Saxony ruled in favour of the claims of Count Ernst.

While regent Count Ernst was snubbed by the German Emperor after writing to William II complaining that the officers of the local garrison did not salute his children, did not address them by the correct style for a ruling family, and that the commanding general at Detmold had personally ordered this.

Moreover, I forbid once for all the tone in which you have seen fit to write me.Ernst remained as regent until his death in Schloss Lopshorn at which point his son Leopold succeeded him as head of the Lippe-Biesterfeld line and regent, before becoming the reigning Prince of Lippe four months later on the death of Prince Alexander.