Basiliscus, who had returned to Constantinople after the disastrous expedition against the Vandals, had been forced to seek sanctuary in the church of Hagia Sophia to escape the wrath of the people.

Leo I had given him imperial pardon, but had banished him for three years to Heraclea Sintica (Thrace).

Zeno, as member of the protectores domestici, had not taken part in the expedition.

In 469, during which he holds the honor of the consulate, he is appointed magister militum per Thracias and leads 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 had asked for Daniel the Stylite's opinion about the campaign, and Daniel had answered that Zeno would have been the target of a conspiracy but would have escaped unharmed.

What happened was that Leo had sent some of his personal soldiers with Zeno to protect him, but they had been bribed by Aspar to actually capture him.

Zeno had been informed of their intention and fled to Serdica, and because of this episode, Leo grows even more suspicious of Aspar.

After the attack, Zeno had not returned to Constantinople, where Aspar and Ardabur are and have still considerable power.

Instead, he moves to the "Long Wall" (the Chersonese Long Wall or, less probably, the Anastasian Wall), then to Pylai and from there to Chalcedon.

While waiting here for an opportunity to return in the capital, he is appointed magister militum per Orientem.

He takes the monk Peter the Fuller with him and leaves for Antioch, his office's see, passing through Isauria, where he puts down the rebellion of Indacus.