Original sentence: At the eve of the 20th century, it changed its exclusively Bulgarian character and opened it to all Macedonians and Thracians regardless of their nationality.Initially the membership was restricted only for Bulgarians.It was active in Macedonia, but also in Thrace (the Vilayet of Adrianople).The Organization gave a guarantee for the preservation of the rights of all national communities there
Edited sentence: At the eve of the 20th century, the Organization gave a guarantee for the preservation of all national communities there.IMARO also changed its exclusively Bulgarian character and opened it to all Macedonians and Thracians regardless of their nationality