Complex sentence: A key figure in the early bank was Jean (John) Pesmatzoglou, an Alexandrian private banker who merged his bank with Bank of Athens, he became the bank's chairman in 1896, and formed an alliance with Banque de l'Union parisienne in 1904.
Split into simpler sentences: A key figure in the early bank was Jean (John) Pesmatzoglou, an Alexandrian private banker who merged his bank with Bank of Athens. He became the bank's chairman in 1896, and formed an alliance with Banque de l'Union parisienne in 1904.