From Camden’s ‘Britannia’ (1695):
“At a little distance upon the very descent of Chiltern Hills, there is a round military fortification.. called Madning-bowre and Madin-boure... The swineherds now and then in the neighbouring fields find coins of the emperors, which they call to this day Madning money.”
(Quoted in the Victoria County History for Bedfordshire, v1 (1904)).