Complex sentence: It was the first to value the lives of the dead and to consider the feelings of mourning relatives left behind, and it was the first occasion in the history of the British Army that recognised the testimony of ordinary soldiery as well as that of the officers.
Split into simpler sentences: It was the first to value the lives of the dead, and to consider the feelings of mourning relatives left behind. And it was the first occasion in the history of the British Army that recognised the testimony of ordinary soldiery as well as that of the officers.