Researchers estimated that the complex built above the Cave of the Patriarchs was built by Herod. A new carbon-14 date reinforces this opinion. The complex was built over a cave, seemingly a natural karst void, possibly modified by humans, traditionally associated with the burial Cave, where Judaisms Patriarchs and Matriarchs are interred - defining the compound as a Heroon, enclosed by a temenos. A concealed burial loculus meant for a single ossuary was discovered in the system below the floor of the temenos. Considering all the data, we would like to suggest that the Heroon-temenos was built at the beginning of Herods reign and the individual burial loculus was set apart for Herod himself before he opted for burial in Herodium.
Cochva et al. (Wed,) studied this question.