The island contains a very large number of important prehistoric monuments.
The Old Church, founded in the 11th century, but in its present form dating from 1476, contains the monuments of two famous admirals of the 17th century, Martin van Tromp and Piet Hein, as well as the tomb of the naturalist Leeuwenhoek, born at Delft in 1632.
A picturesque avenue leads to the church of St Mary, principally Early English and Perpendicular, with remains of Norman work, having a lofty tower surmounted by a spire, and containing several fine monuments, tombs and brasses.
The Keftiu who represented Minoan culture in Egypt in the concluding period of the Cnossian palace (Late Minoan II.) cease to appear on Egyptian monuments towards the end of the XVIIIth Dynasty (c. 1350 B.C.), and their place is taken by the "Peoples of the Sea."
The old church of Mortlach, though restored and almost renewed, still contains some lancet windows and a round-headed doorway, besides monuments dating from 1417.