<u><em>The Ottoman Empire, also known as the Ottoman Turkish Empire</em></u>.
<u>The Ottoman Empire began as one of the small Turkish states</u> <em><u>that emerged in Asia Minor during the decline of the Seljuk Empire</u></em>.
<em><u>The Ottoman Turks gradually controlled the other Turkish states</u></em>, <u>and continued to expand at the expense of the territories of the Byzantine Empire</u>.
<u><em>The answer is</em></u>: <u>Byzantine Empire</u>.