A Duchy was a dukedom, or an area of land owned by a Duke. In this case, the Duke of Mecklenburg-Schwerin had been elevated in 1815 to the status of Grand Duke as he acquitted himself well in helping to defeat Napoleon in the Napoleonic Wars. Hence his lands changed from the Duchy of Mecklenburg-Schwerin to the Grand Duchy of Mecklenburg-Schwerin.
Prior to 1871, the area we now refer to as Germany was a conglomeration of three dozen loosely allied German states. People considered themselves Prussians, Bavarians, Hessians, Pomeranians, or Mecklenburgers to name just a few. In the 17th and early 18th centuries, the Grand Duchy of Mecklenburg-Schwerin was a primitive feudal society with the majority of the land being owned by wealthy landowners. The landowners controlled the economy and ruled their estates with absolute authority. Although many of the peasants did own small pieces of land, they lived in terrible poverty and had few rights. They needed to seek the permission of the landowner to move from town to town, to emigrate, or even to marry.
By 1820, serfdom was repealed but this helped the people little. It meant they no longer had to work for the landowner but it also meant the landowner was no longer responsible for caring for them or housing them! Peasants who did not have their own land were even poorer than before. They basically worked from sunrise to sunset for starvation wages. This area was one of the poorest of the German states and this may account for the huge numbers of Mecklenburg
emigrants to North America in the 19th century – approximately one quarter of the population left between 1820 and 1890.