1700s, really? I’d like to know more about this. I thought the last (officially) pagans in Europe were Lithuanian, in the 14th or 15th century. Thanks.
Note, not all the people of the Northern Polar regions were Christianized simultaneously with the Danes. The Orthodox were sending missionaries into the Sapmai to Christianize the Sa'ami well into modern times.
They were hardly alone ~ plus, not all the Mongols went home (and many were Buddhist), and not all the Turkish POWs were repatriated (with good numbers of them being Orthodox and not Roman, and if not, then Moslem, and possibly even Shi'ite, not Sunni).
The various claims about uniformity of Christianization throughout Europe are just that ~ claims! Not everyone was on the same page at the same time, and knowing that the big blow up in the 15th and 16th centuries should have been expected.