The family story was that two brothers came over the mountains from Russia and married in Schleswig-Holstein... how romantic is that!
from Prussia? - early 1800's I have two brother's, with variations of surname, immigrated, living and listed in Danish census. But our records go back to early 1700's living in Schleswig. This is an area I have yet to look at more closely, as there are a couple of families that I havn't connected yet.
Central Europe - covers Bohemia, Romania, Slovakia - these three countries spoke Czech and German, and the only language I can find a link for 'Sladit' is czech, croatian, and Slovakian... so the strongest link is to that area as origin of name at least.
All these countries suffered the 'reformation blues' with Protestant uprisings, and Catholic reprimands, and the 30 years war started in 1620 which decimated a large part of Germany.
However - Our ancestors remain within a small locality, 'Dithmarchen', within Schleswig-Holstein, for 300 years of births, deaths, and Marriages... so very strongly attached to this area. The history of the Dithmarches show they are noted for their fierce independance. They also baptised their children into the Lutheran Church - which may mean something, or not at all.
There are many possibilites - maybe following the 30 years war, they immigrated there, given that there would have been a loss of population, and workers needed; maybe before/during/ or after due to religious persecution; maybe they got caught in the many, many battles or this war torn era?
The oldest recorded direct ancestor’s surname is Johan Sladetzki, a Danish soldier, and it continued as Sladetzki from 1675 to around 1807, when it changed from Sladetzki to Schladetsch with Paul Hinrich.
The 'zki' ending is not a strong Russian suffix, but has rather a Polish/ central Europe influence. It just means 'of the'.
The Sweet Theory:This my 'pet' idea. Central Europe covers a large area including Bohemia, Romania, Slovakia and these three countries spoke Czech and German. The only language I can find a meaning for 'Sladit' is in Czech, Croatian, and Slovakian. Sladit means sugar or sweet. So there is a strong link to that area as an origin of the name. In which case Sladit + zki would mean Sweet + of the, so maybe sugar beet farmers, or Honey keepers.
Slav People group Theory:
The Slavs arrived in the territory of present day Slovakia in the 5th and 6th centuries
Germans settled in the northern territory of the Kingdom of Hungary (territory of present day Slovakia) from the 12th to 15th centuries (see Ostsiedlung), mostly after the Mongol invasion of 1241. There were probably some isolated settlers in the area of Pressburg earlier. The Germans were usually attracted by kings seeking specialists in various trades, such as craftsmen and miners. They usually settled in older Slavic market and mining settlements.
But the Ottoman wars and frequent insurrections against the Habsburg Monarchy also inflicted a great deal of destruction, especially in rural areas. The Turks withdrew from Hungary in the late 17th century.
It is also then possible that following a return immigration to Germany, their surname is a deriviation or combination of Slav + deutsch + zki = Sla + det + zki. Meaning they came from Germany and Slovakia, or where German speaking Slovavians.
Variations of Surname:
These are some obvious and not so obvious possible surname deviations:
Schladot = ‘ot’ suffix is a Hebrew plural ending.
So this is really all guesswork at this stage, until someone can come up with a better, or more concrete answer.