They are all from the Wettin dynasty but at different times ruled over different parts of Saxony/Thuringia, including Meissen. About 1400 they inherited the Electorate of Saxony and about 50 years later split into two major lines, the Ernestine and Albertine.
The elder Ernestine line lost the Electorate and split into many minor families including Sachsen (or Saxe) Gotha, Saalfeld, Altenburg, Coburg etc and were the Royal families of Belgium, Great Britain, Portugal, Bulgaria etc
The Albertine line inherited the Electorate and then became Kings of Saxony (or Sachsen as it should be), and were also Kings of Poland. They also split into 3 minor branches ; Weissenfels, Merseburg and Zeitz but none of them survived beyond three or four generations.
There are probably more LNABs for this family and I'm not sure there is an easy answer as to what they should be called. Technically they should all be Wettin, but it's difficult to justify this as the LNAB for Queen Elizabeth II for instance.
personally I think they should be Wettin for the beginning of the dynasty but once they are firmly established as ruling a particular country/territory that name takes precedence.
Further comment - although complete consistency in naming noble/royal families is a wonderful ideal, it would involve an enormous effort to change all the Wettin family, even if we could decide on the most appropriate name for them all, and that's just one family. Also from what I can gather, making many changes to the LNAB can stuff up searching Wikitree.
Where the LNAB doesn't fit in with the naming standard such as it includes a pre-surname, or is in an inappropriate language then it needs to be changed but otherwise if it is a name that is applicable to the family then I think it needs to stay.
There has been a lot of work on the categories recently by some hard working people and that is where I think you can consistenly link all the Wettin and other families into one group, rather than through the LNAB.
