Complex sentence: It was edited by JaanTõnissonwho made Postimees the most important Estonian newspaper back then, which brought together many talentedculturalfigures such as August Kitzberg, Anna Haava and Karl August Hindrey.JaanTõnisson was also a long-time editor of the newspaper in theindependentRepublic of Estonia.
Split into simpler sentences: It was edited by Jaan Tõnisson who made Postimees the most important Estonian newspaper back then, which brought together many talented cultural figures such as August Kitzberg, Anna Haava and Karl August Hindrey. Jaan Tõnisson was also a long-time editor of the newspaper in the independent Republic of Estonia.