Stand on the open heathland six miles north of Sleaford, and you can still feel it: the particular silence of a place that once held great power. (Well, actually not that silent, the birdsong in the hedgerows was almost deafening when I went there).

A single limestone tower rises above the farmyard, weathered but still standing tall, its spiral staircase worn smooth by eight centuries of footsteps.

This is Temple Bruer: the most important Knights Templar preceptory in England outside London, and a place that has fascinated me ever since I began researching the medieval world of Nicola de la Haye.