Complex sentence: In 1954, C.K. Brain began working at sites in the Cradle including Coopers and he soon would initiate his three-decade work at Swartkrans cave which would result in the recovery of the second largest sample of hominid remains from the Cradle.
Split into simpler sentences: In 1954, C.K. Brain began working at sites in the Cradle, including Cooper's Cave. He soon would initiate his three-decade work at Swartkrans cave; it would result in the recovery of the second-largest sample of hominid remains from the Cradle.