On one of my more bizarre days out with my Pentax ME Super was to Hythe, in Kent. The parish church of St Leonards has an “Ossuary”, no I didn’t know that that was either! Another name is “bone house”.
There are many theories as to who and why these are in the crypt. The most recent and most likely correct is that of a survey that took place between 2009-2012 which reported that:
“they were Hythe residents who died over a long period and had been buried in the churchyard (evidenced by the deposits of soil within the skulls), and that the earliest of the remains were dug up in the 13th century when the church was extended eastwards over their previous graves. However, this number of individuals is high for ‘Hythe only’ residents, and the collection probably includes bones from four graveyards in the Hythe area that are said to have fallen out of use and closed by 1500”
You can read the full story here