Complex sentence: These two communities, split by the Sandusky River, were rivals; however, in 1850, seeing that later their interests lay together, the villages merged to form Tiffin, with Fort Ball becoming a part of Tiffin in March of that year.
Split into simpler sentences: These two communities, split by the Sandusky River, were rivals. But, in 1850, seeing that later their interests lay together, the villages merged to form Tiffin, with Fort Ball becoming a part of Tiffin in March of that year.