Ahmed Bey ben Mohamed Sherif, also known as Ahmed Bey or Hadj Ahmed Bey was the last bey of Constantine in the Regency of Algiers, ruling from 1826 to 1848. He was the successor of Mohamed Menamenni Bey ben Khan. As head of state, he led the local population in a fierce resistance to the French occupation forces. With the position vacant, in 1833 he adopted the title of leader of Algeria, and dey in exile، although this was not recognized by any other country. In 1837 Constantine was taken by the French after an intense siege. He retreated into the Aurès Mountains from where he continued to wage a low-intensity conflict with tribes still loyal to him, until he capitulated in 1848.

Constantine, also spelled Qacentina or Kasantina, is the capital of Constantine Province in northeastern Algeria. During Roman times it was called Cirta and was renamed "Constantina" in honour of Emperor Constantine the Great. Located somewhat inland, Constantine is about 80 kilometres from the Mediterranean coast, on the banks of the Rhumel River.