Twenty-seven radiocarbon results are now available from the Fussell's Lodge long barrow, and are presented within an interpretive Bayesian statistical framework. Three alternative archaeological interpretations of the sequence are given, each with a separate Bayesian model. It is hard to decide between these, though we prefer the third. In the first (following the excavator), the construction is a unitary one, and the human remains included are by definition already old. In the second, the primary mortuary structure is seen as having two phases, and is set within a timber enclosure; these are later closed by the construction of a long barrow. In that model of the sequence, deposition began in the thirty-eighth century cal. bc and the mortuary structure was extended probably in the 3660s–3650s cal. bc; the long barrow was probably built in the 3630s–3620s cal. bc; ancestral remains are not in question; and the use of the primary structure may have lasted for a century or so. In the third, preferred model, a variant of the second, we envisage the inclusion of some ancestral remains in the primary mortuary structure alongside fresh remains. This provides different estimates of the date of initial construction (probably in the last quarter of the thirty-eighth century cal. bc or the first half of the thirty-seventh century cal. bc) and the duration of primary use, but agrees in setting the date of the long barrow probably in the 3630s–3620s cal. bc. These results are discussed in relation to the development and meanings of long barrows at both national and local scales.