Strasbourg:

In 1871, after the end of the war, the city was annexed to the newly established German Empire as part of the Reichsland Elsass-Lothringen under the terms of the Treaty of Frankfurt. As part of Imperial Germany, Strasbourg was rebuilt and developed on a grand and representative scale, such as the Neue Stadt, or "new city" around the present Place de la République. Historian Rodolphe Reuss and Art historian Wilhelm von Bode were in charge of rebuilding the municipal archives, libraries and museums. The University, founded in 1567 and suppressed during the French Revolution as a stronghold of German sentiment,[citation needed] was reopened in 1872 under the name Kaiser-Wilhelms-Universität.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". What was the Treaty in 1871 called?
Treaty of Frankfurt