Mentuhotep II, the 21st century BC founder of the Middle Kingdom, is recorded to have undertaken campaigns against Kush in the 29th and 31st years of his reign. This is the earliest Egyptian reference to Kush; the Nubian region had gone by other names in the Old Kingdom.[15] Under Thutmose I, Egypt made several campaigns south.[16] This eventually resulted in their annexation of Nubia c. 1504 BC. After the conquest, Kerma culture was increasingly Egyptianized, yet rebellions continued for 220 years until c. 1300 BC.