Complete the sentence.The proposed constitution that opened up the voting rights to all free adult men in 508 B.C.E. was written by .

The proposed constitution that opened up the voting rights to all free adult men in 508 B.C.E. was written by Cleisthenes. Known as the "Father of Athenian Democracy," Cleisthenes introduced a series of reforms that significantly expanded the political participation in Athens. His political structure dismantled the aristocratic power bases and encouraged broader representation. The reforms he implemented included the establishment of new voting districts and councils, allowing ordinary citizens to have a voice in the governance of Athens. This marked a significant transformation in the political landscape of ancient Greece, paving the way for a more participatory form of governance that is often regarded as the origins of modern democracy.