Zeno, as a member of the "protectores domestici", did not take part in the disastrous expedition against the Vandals, led in 468 by Leo's brother-in-law Basiliscus. The following year, during which he held the honour of the consulate, he was appointed "magister militum per Thracias" and led an expedition in Thrace. The sources do not clearly state what enemy he fought there, and historians had proposed either Goths or Huns, or the rebels of Anagastes. Either way, before leaving, Leo and Zeno asked for Daniel the Stylite's opinion about the campaign, and Daniel answered that Zeno would be the target of a conspiracy but would escape unharmed. Indeed, Leo sent some of his personal soldiers with Zeno to protect him, but they were bribed by Aspar to capture him instead. Zeno was informed of their intention and fled to Serdica, and, because of this episode, Leo grew even more suspicious of Aspar.