Complex sentence: On 17 April 1910, Wallis was confirmed at Christ Episcopal Church, Baltimore, and between 1912 and 1914 her uncle Warfield paid for her to attend Oldfields School, the most expensive girls' school in Maryland.
Split into simpler sentences: On 17 April 1910, Wallis was confirmed at Christ Episcopal Church, Baltimore. Between 1912 and 1914, her uncle Warfield paid for her to attend Oldfields School, the most expensive girls' school in Maryland.