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The leper hospital of St. Giles lies over a mile to the west of London proper, a walled compound surrounded by fields and marshes. It was founded in 1117 by Queen Matilda, wife if King Henry I, on the site of an old and largely derelict Saxon church. Its walled compound holds that church - now largely rebuilt in the Norman style - along with fields, workshops, sleeping quarters, and a small orchard, making it a largely self-sufficient agricultural commune.
When Adam Bell arrived in London in 1127, St. Giles was largely ignored by the Kindred. The hospital foundation was too small to provide a decent herd, and lacked the resources and political connections that made other religious institutions a target for Kindred manipulation, despite its royal founder. Mithras asked Adam what he was seeking in London, and Adam replied that he was looking for a place where he could practice his healing skills and minister to the poor. Mithras was indifferent to Adam's humanitarian ambitions, but they did offer a cheap way to keep this potentially useful neonate available and out of mischief, by granting him a Domain that no-one else was interested in claiming. The Prince named Adam the master of the lazar-house of St. Giles.
The original bequest establishing the hospital had made provision for fourteen lepers, one clerk, and one messenger, besides matrons, the master, and other members of the establishment. In 1127, the Proctor of the hospital was a man named Walter Courcelles, a grizzled old veteran of the First Crusade who'd sought a religious vocation after his persistent nightmares about the sack of Jerusalem in 1099 left him in terror for the state of his soul. Mithras had expected Adam to ghoul Courcelles as a matter of course, but Adam considered the Blood Oath a blasphemous violation of the Divine gift of free will. Instead, he persuaded Courcelles to become a willing ally, offering him consolation, spiritual guidance, and above all, understanding of the horrors that had haunted his dreams. The Proctors and clerks since then have all followed that pattern, dedicated and pious physicians willing to accept the leadership of a Cainite if it's in the best interest of the leper community that they care for. Many of the lepers themselves are also aware of Adam's true nature, but remain loyal to him nonetheless thanks to his dedication to their well-being and skill as a physician.
St Giles is also a "parish church" of sorts for London's Faithful Nosferatu, who come there to take Confession with Father Adam.