 He succeeded his father as Duke of Saxe-Hildburghausen when he was only eighteen years old in 1745; as a result his mother, the Dowager Duchess Caroline, acted as a regent on his behalf until he reached adulthood, in 1748.Ernst Frederick was considered to be intelligent, talented, and one of the most handsome princes of his time.He donated a library to the city, but finally his excessive prodigality in exaggerated yard and military splendor drew the attention of the highest places to the financial situation of his country.