The Mare Glaciale region, some 440 years ago:
Map of the North Atlantic region, Sigurdur Stephansson (1570), published in The Geology of North America, Vol. L, The Arctic Ocean region, The Geological Society of America, 1990, p. 7.
For one history of Arctic Ocean bathymetry through 1983 see J.R. Weber, Maps of the Arctic Basin Sea Floor: A History of Bathymetry and its Interpretation, in: Arctic, vol. 36, no. 2 (June 1983), pp. 121-142.