Simplify the following text for a Grade 9 native English-speaking person.
Original: The lake was the center of Urartian kingdom from about 1000 BC and the capital of Urartu , Tushpa , was on the shore of Lake Van ( on the site of the medieval castle of Van , west of Van city ) .
Simplified: Tushpa , the capital of Urartu , was located near the shores of Lake Van , on the site of what became medieval Van 's castle , west of present-day Van city .