Final answer:
The Vikings, also known as Varangians in the east, are the group that invaded the Slavic homeland beginning in the ninth century.
Step-by-step explanation:
The group that invaded the Slavic homeland beginning in the ninth century was the Vikings.
The Vikings, originating from Scandinavia, embarked on numerous raids across Europe, including the Slavic territories. Their ventures eastward along rivers such as the Dnieper led to settlements and important trading connections, notably establishing what would become one of the first Russian states with Kyiv as a central locale. Referred to as Varangians in the East, they carved out new territories, paving the way for further Norse expansion and settlement.
Among their many activities across Europe, these Norsemen were instrumental in shaping the historical landscapes of the regions they invaded, including that of the Slavic peoples.