when did the vandals capture this place?
420s
Mauretania
The Vandals conquered the Roman province beginning in the 420s. 
which emperor loved greek culture and adopted the wearing of a beard UNANSWERABLE where did caligula reign/ Rome. during which time? AD 37 to 41. who was his predecessor? Tiberius. who plotted against him? Cassius Chaerea. whom did he marry? UNANSWERABLE did he take part in any battle? Yes, during his reign, the empire annexed the client kingdom of Mauretania as a province. where is this located? It stretched from central present-day Algeria westwards to the Atlantic, covering northern Morocco, and southward to the Atlas Mountains.
wiki:13491121
Mauretania [SEP] Vandal kingdom
The Vandals conquered the Roman province beginning in the 420s. The city of Hippo Regius fell to the Vandals in 431 after a prolonged siege, and Carthage also fell in 439. Theodosius II dispatched an expedition to deal with the Vandals in 441, which failed to progress farther than Sicily. The Western Empire under Valentinian III secured peace with the Vandals in 442, confirming their control of Proconsular Africa. For the next 90 years, Africa was firmly under the Vandal control. The Vandals were ousted from Africa in the Vandalic War of 533–534, from which time Mauretania at least nominally became a Roman province once again.