Radiocarbon dating of the remains suggested Early Neolithic activity began at the site during 3980 – 3800 calibrated BCE ( 95 % probability ) or 3960 – 3880 cal BCE ( 68 % probability ) , when the first human remains were buried at the site . It then suggested that after an interval of either 60 – 350 years ( 95 % probability ) or 140 – 290 years ( 68 % probability ) , further depositions of human remains were made inside the tomb . This second phase probably began in 3730 – 3540 cal BCE ( 95 % probability ) or 3670 – 3560 cal BCE ( 68 % probability ) . The radiocarbon dating of the human remains does not provide a date for the construction of Coldrum Long Barrow itself ; it is possible that the individuals died either some time before or after the monument 's construction .