I-M223-Cont1

Using this internet I-Hg subclade predictor and entering in the 37-marker values from FTDNA, my dad's Y-Hg prediction is I-M223-continental 1 with a greater than 97% probability. 

I'm speculating, but I bet the continental-1 descriptor might correspond to Germanic Anglo-Scandinavian tribes and to one the regions of Angeln or Saxony in Germany and/or to southern Sweden (southern Sweden is the location of my own autosomal DNA deep ancestry). 

"The Anglo-Saxons are a Scandinavian people from northern Germany, Denmark and the Frisian Islands, with some additional links to southern Sweden." 

I2b1 (I-M223) peaks in both Germany and Sweden, and can be found also in Anglo-Saxon England, Ireland and Scotland. Continental 1 probably refers to continental tribes possibly from one of the areas in Germany, Denmark or Sweden in contra-distinction to Anglo-Saxon England and the Frisian Islands which are NOT continental but islands. Supporting this idea, I've also read that continental I2b1's are unlikely to test positive for the downstream SNP marker M284 (the I2b1a subclade marker which is found almost exclusively in Britain).

So, my working hypothesis right now is that I-M223-cont1 refers to Germanic Anglo-Scandinavians.