Most likely some where back in the generations, a good percentage of the Mussons are related. As to how they moved and why, it is just like today. For better living, likely. My line were from London, they went to Canada in about 1822.Most likely it was to expand thier resources. They most likely trade back and forth between England and Canada. They were very well educated, which was not the norm for this time period. This family was a member of the gold guild in London, so had money when they came to buy large farms and expand into mills, distrilleries and export/import businesses. They also each had 10 or more children, so needed a good income to raise that large of family.