Complex sentence: From 1809, his childhood friendship with Maria Bicknell developed into a deep, mutual love but their engagement in 1816 was opposed by Maria's grandfather, Dr Rhudde, rector of East Bergholt, who considered the Constables his social inferiors and threatened Maria with disinheritance.
Split into simpler sentences: From 1809, his childhood friendship with Maria Bicknell developed into a deep, mutual love. Their engagement in 1816 was opposed by Maria's grandfather, Dr Rhudde, rector of East Bergholt, who considered the Constables his social inferiors and threatened Maria with disinheritance.