As Portus Adurni, Portchester in present-day Hampshire was established as one of the ‘forts of the Saxon shore’, built by the Romans along the southeastern English coast in the 3rd century CE. At the time, Roman Britannia was suffering increasingly from cross-channel marauding from north European tribes. The ‘Count of the Saxon Shore’ became one of the three main military commands in Roman Britain holding authority over forts on both sides of the Channel: Count Theodosius would go on to become Roman emperor in 379. After the Roman withdrawal in the 5th century, the fort became a Saxon stronghold, and in 904 was acquired by Edward the Elder as part of the expanding proto-English kingdom. The medieval castle was probably built by William Maudit, a henchman of William the Conqueror. It would play host to several English kings before falling into disuse: it was a prison hospital in the Napoleonic Wars.
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