Complex sentence: Nevertheless, border disputes between Persia and the Ottomans did not end, and between 1555 and 1918, Persia and the Ottoman empire signed no less than 18 treaties re-addressing their disputed borders.
Split into simpler sentences: Nevertheless, border disputes between Persia and the Ottoman Empire did not end. Between 1555 and 1918, Persia and the Ottomans signed no less than 18 treaties that would re-address their disputed borders.