Complex sentence: St Katharine Cree is regarded as one of the most significant churches of the Jacobean period, a time when church-building was at a historically low ebb, and is the only Jacobean church to have survived in London.
Split into simpler sentences: St Katharine Cree is regarded as one of the most significant churches of the Jacobean period, a time when church-building was at a historically low ebb. It is the only Jacobean church to have survived in London.