 There is evidence the Second Bulgarian Empire, at least nominally, ruled the Wallachian lands up to the Rucăr–Bran corridor until the late 14th century.In a charter by Radu I, the Wallachian voivode requests tsar Ivan Alexander of Bulgaria to order his customs officers at Rucăr and the Dâmboviţa River bridge to collect taxes following the law.The presence of Bulgarian customs officers at the Carpathians indicates Bulgarian suzerainty over those lands, though Radu's imperative tone implies a strong and increasing Wallachian autonomy.