In the follwoing sentences below, what do you think is the best interpretation of the meaning of "them to develop"?

"The Chinese people to think" or "the conceptions of race and nation to be defined"?

(The second one seems wrong in grammatical senses though...)  

Any idea would be a big help for me. My opinion is in bold blue below.

Consider this simpler example.

Before the accident, he did not have so painful a back as the accident led hin to develop.

This means the accident led him to develop a more painful back.

Since the bond of the Empire was cultural and since the Empire should include all civilized
mankind, racial distinctions were not so marked as in most other parts of the world. The Chinese
did not have so strong a sense of being of different  blood from non-Chinese as twentieth-century conceptions of race and nation later led them to develop a (stronger) sense of being of different  blood from non-Chinese . They were proud of being “the sons of Han” or “the men of T’ang,” but if a people fully adopted Chinese culture no great distinc tion was perceived between  them and those who earlier had been governed by that culture.

Best wishes, Clive