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Agnes of Landsberg (1192 or 1193 – 1266 in Wienhausen) was a German noblewoman. She was the third child of Conrad II (1159–1210), Margrave of Lusatia, and his wife, Elisabeth ( – 1209), the daughter of Mieszko III the Old (1126–1202), Duke of Poland. She was a daughter-in-law of Henry the Lion.