Return to the Roots or RttR is an open source add-on type of remake of The Settlers II. This means it requires the original game files in order to work as Ubisoft did not give Settlers Freaks (the group developing RttR) a permission to redistribute the files. This means you need The Settlers II: Gold Edition for RttR to work.
This is the Stable version 0.9.1 of RttR for Windows(x64). Latest Versions and Nightly Builds on siedler25.org
<3