Complex sentence: In 1906, the bank acquired Industrial Credit Bank (Τράπεζα Επαγγελματικής Πίστεως; est.1873 in Athens) which had opened a branch in Istanbul in 1905 that was transferred to Bank of Athens.
Split into simpler sentences: In 1906, Bank of Athens acquired Industrial Credit Bank (Τράπεζα Επαγγελματικής Πίστεως; est.1873 in Athens). It had opened a branch in Istanbul in 1905 and this transferred to Bank of Athens.