[blam]

"Many Portuguese maps were lost for posterity when the repository, the Casa da India, in Lisbon was destroyed by an earthquake in 1755."

Looks like this map survived because of a catastrophe.

[Fred Nerks]

http://www.fordham.edu/halsall/mod/1755lisbonquake.html

“That was the year when Lisbon town /Saw the earth open and gulp her down.”