The 3rd earl of Rochford, a relation of  William of Orange and the Nassau family, rebuilt it in the 18th Century.  Later owners included Brandreth, who demolished part of the Georgian wings. Sir John Johnson, who built the high Victorian banqueting hall behind the 16th Century oriole window, and Somerset de Chair, who restored the gate house.  De Chair's fourth wife, Lady Juliet Fitzwilliam, brought her fine art collection to the Priory and it was opened to the public, following many years as a convalescent home. it is now a private home.

POINT CLEAR, to the west of the village centre, developed in the 1920's although most of the holiday homes have now been replaced by modern houses. There is a Martello Tower at the western end opposite Brightlingsea, currently housing a an aviation museum. St Osyth by pass was built in the 1930's and development has in-filled what were seed-growing fields, Carters Tested Seeds were grown here in the 1880's - and later allotments. St Osyth Beach and the low lying parts of Point Clear started as typical holiday destinations with beach huts but in the 1953 floods these areas have now been developed as caravan Holiday Villages with extensive facilities for visitors.

WILDLIFE

St Osyth supports some of the finest wildlife and natural features in Essex.  Large parts of the parish have areas designated as Sites of special Scientific Interest (SSSIs).  The coastal strip all the way round from St Osyth Beach around Point Clear to the head of flag Creek forms part of the Colne Estuary SSSI.  Another SSSI is the ancient woodland of riddles wood, off Clay Lane and a geological SSSI is sited at a section of a disused mineral working, once part of an ancient route of the River Thames.  Two areas within the coastal SSSI are owned and managed as nature reserves by the Essex Wilde Life Trust - Colne Point and Howlands Marsh.

FOOTPATHS

St Osyth wonderful network of public footpaths, lanes and beaches enables much of its wealth of flora and fauna to be admired by those who appreciate it.  Three of the main public footpaths enable walkers to enjoy fine views over the salt-marshes, grazing marshes, sand marshes and shingle ridges, creeks, sand and mud flats of the coastal SSSI.  One heads westwards along the sea wall from St Osyth Beach, overlooking Colne Point.

A second sea wall walk takes you from the dam, or Mill Street Causeway, along the south side of St Osyth Creek, to Point Clear Bay.  A third, on the opposite side of the creek, takes you from the Quay to Colchester Road. It passes along the edge of Howlands Marsh, Where courtesy paths leading to two hides are normally available for careful members of the public to view feeding, nesting and resting birds.