The excavations of a huge tidal dock on the left bank of the Scheldt river near Doel (Belgium) provided an excellent opportunity for the study of the stratigraphy and palaeoecology of the Holocene deposits in the Lower Scheldt polders. A complete organic sequence from the period between 6000 and 1400 BP was radiocarbon dated and investigated by means of pollen, spores and other microfossils, macroremains and diatoms. Besides a good developed sequence of the botanical evolution since the Atlanticum, interesting information on two specific events was obtained. Firstly the extension and conditions of the late Calais inundation, between 5800 and 5000 BP could be reconstructed. Secondly it became possible to gain more insight in the timespan between the end of the peat growth around the 6th-7th century AD and the large strategic inundation after 1580 AD. A period of non deposition followed by local deposits of late medieval military storm surges could be recognised.