Complex sentence: The school got its first academic recognition from the University of Calcutta in 1944, through the untiring efforts of former Education Officer, the late Haji Azizur Rahman, who served as headmaster at the school in 1950--56.
Split into simpler sentences: The school got its first academic recognition from the University of Calcutta in 1944, through the untiring efforts of former Education Officer, the late Haji Azizur Rahman. The late Haji Azizur Rahman served as headmaster at the school in 1950--56.