Complex sentence: Among other firsts, Harrison's victory was the first time the Whig Party had won the presidential election, but he died after a month in office, and his running mate John Tyler served the remainder of his term, quickly breaking with the Whigs.
Split into simpler sentences: Among other firsts, Harrison's victory was the first time the Whig Party had won the presidential election, but he died after a month in office. His running mate John Tyler served the remainder of his term, quickly breaking with the Whigs.