Complex sentence: The Dutch Reformed Church expanded to the Americas, beginning in 1628 with Marble Collegiate Church in New York City (then called New Amsterdam), As the Netherlands started colonies across the continent, the Dutch Reformed became the first official denomination.
Split into simpler sentences: The Dutch Reformed Church expanded to the Americas, beginning in 1628 with Marble Collegiate Church in New York City (then called New Amsterdam). Wherever the Netherlands started colonies, the Dutch Reformed became the first official denomination.