He was born on 13 June 823 in Frankfurt, when his elder brothers were already adults and had been assigned their own regna, or subkingdoms, by their father.
Karl dilahirkan pada tanggal 13 Juni 823 di Frankfurt, ketika saudara-saudaranya telah beranjak dewasa dan telah mendapatkan regna, atau pembagian kerajaan mereka sendiri, dari ayahanda mereka.