Explorer II = Minerva; Alexander von Humboldt II = Jules Verne

It used to be so simple:

"Explorer" was the former "Lindblad Explorer" that turned into "Society Explorer" and finally "GAP Explorer" or simply "Explorer".

Then there was "Explorer II", which was at times also "Alexander von Humboldt" when it was operated by Phoenix Reisen. Otherwise Abercrombie & Kent would call her "Explorer II", simply because they used to charter the original "Explorer" before.

But now Phoenix Reisen does not charter the same vessel any more, so one would think that A & K have it all to themselves.

But wait: while Phoenix Reisen is now chartering the "Jules Verne" - calling her "Alexander von Humboldt II" - the new owners of the vessel, Swan Hellenic have come up with an idea: why not rename "Explorer II" into "Minerva" (again)?

Meanwhile, the original "Explorer" is assumed to have sunk, while the expedition cruiser "Alexander von Humboldt" simply ceased to exist...

And did I mention that the previous operator of the "Explorer", Lindblad Expeditions, is now refitting a former Hurtigruten ship, the former Lyngen, and they will call her National Geographic Explorer.

As usual, Wikipedia helps solve these and other riddles. Here is a list of cruise ships, replete with dates and previous names!