You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "Who was noted for their long resistance (1219–1290) against the German crusaders and Teutonic Knights during the Northern Crusades, who had a duke in the second half of the 13th century who uled in the western part of Semigallia?" whose answer is Semigallians.
Each document should contain about 30 words, and these documents should contain useful information.

Query: rulers of Semigallia 13th century
Useful Output:

Doc 1: Since ancient times, Semigallia has been associated with wealth, greatness, its kings and the tempered character of Semigallian people. Dobe (Incēni) Hillfort
Doc 2: The Duchy of Courland and Semigallia was dissolved and it became a Russian province in the course of the third partition of Poland in 1795.
Doc 3: Comments ; Courland and Semigallia 2 - Persistence (Friedrich/Wilhelm Kettler). Schrodinger's Moose · 1.7K views ; Paganism in twelfth century
Doc 4: Six Semigallian lands were known in the first half of the 13th century: Dobene, Dobele, Silene, Spārnene, Tērvete, Upmale, Žagare. Following
Doc 5: In the 13th century, the lands along the shores of the Baltic Sea are Pagan. The most powerful is the land of Semigallia where even the Vikings fear to tread.