Complex sentence: The phenomenal growth in the fortunes of the company required an expansion in the number of members of the board and the late Dr. Alvan Ikoku and Dr. Amiel Fagbulu became directors in 1971 and 1972 respectively.
Split into simpler sentences: The phenomenal growth in the fortunes of the company required an expansion in the number of members of the board. Thus, the late Dr. Alvan Ikoku and Dr. Amiel Fagbulu were brought on board in 1971 and 1972 respectively.