Complex sentence: When Black Americans finally gained citizenship in 1866, Congress passed the Southern Homestead Act 1866 that was meant to avail land in states such as Alabama, Arkansas, Florida, Louisiana and Mississippi to acquisition by the people including the black population.
Split into simpler sentences: When Black Americans finally gained citizenship in 1866, Congress passed the Southern Homestead Act 1866. This Act was meant to avail land in states such as Alabama, Arkansas, Florida, Louisiana and Mississippi to acquisition by the people, which included the black population.