Emerged rejecting something OR emerged by rejecting something

[chitraaa]

Is the following sentence written by me correct in its construction?
21st century marks the decay of the political system which, rejecting feudalism in favour of democracy, emerged at the end of the 16th century.

 

[emsr2d2]

Is the following sentence (written by me) correct? in its construction?

The 21st century marks the decay of the political system which that, rejecting feudalism in favour of democracy, emerged at the end of the 16th century.