The eastern segment of the Kremlin wall, and Red Square behind it, emerged on its present site in the 15th century, during the reign of Ivan III; the wall and the square were separated with a wide defensive moat filled with water diverted from the Neglinnaya River. The moat was lined with a secondary fortress wall, and spanned by three bridges connecting the Kremlin to the posad. From 1707–1708 Peter the Great, expecting a Swedish incursion deep into the Russian mainland, restored the moat around the Kremlin, cleared Red Square and built earthen fortifications around Nikolskaya and Spasskaya towers. From 1776–1787 Matvey Kazakov built the Kremlin Senate that today provides a backdrop for the present-day Necropolis.