Trewince was built in 1750 by a man called Stephen Johns, but according to the Henderson Calendars (1919 transcripts of unpublished Cornish manuscripts), records of lands at “Trewynsse or Trewense in the parish of St Gerrans” date back to 1571, and maps from an even earlier date show a dwelling at Trewince. Originally Trewince would have been part of the Tregear estate - written records are in the Domesday Book 1085.

Hundreds of years later, the cob walls of the cottage are still intact, rammed into place with a mixture of clay, straw, dung and small stones, solid and rock hard. There is a broad stairway in the house, “wide enough for two crinolines to pass”. The building has some fine architectural features, with examples of ‘chinoise’ open wooden panelling, beautifully ornate cornices and ceilings, and an intricately carved fireplace in the style of Grinling Gibbons.

From the sixteenth century onwards, the Trewince mansion changed and developed; whilst little is known of an earlier building on the site, there was a coach house and cottage, and also gardens, orchards and plantations. The walled garden, still intact, was filled with flowers and fruit trees; there would have been game preserves and dove-cotes.