History of the Peloponnesian War

But whilst he stayed, he wasted the Chalcidean, Bottiaean, and Macedonian territories; and when he could not effect what he came for and his army both wanted victual and was afflicted with the coldness of the season, Seuthes the son of Spardocus, his cousin-german and of greatest authority next himself, persuaded him to make haste away. Now Perdiccas had dealt secretly with Seuthes and promised him his sister in marriage and money with her;

and Sitalces at the persuasion of him after the stay of full thirty days, whereof he spent eight in Chalcidea, retired with his army with all speed into his own kingdom. And Perdiccas shortly after gave to Seuthes his sister Stratonica in marriage, as he had promised. This was the issue of this expedition of Sitalces.