The gorge of the Vardar at modern Demir Kapija was the site of Strez's capital, Prosek, from 1208 to 1214
Prosek (Macedonian alphabet: Просек), also known as Stenae (in greek Στεναί - narrow -), is an archaeological site located in the Demir Kapija Canyon, in Republic of Macedonia. This ancient settlement had an excellent strategical and war position. It was discovered in 1948. Some things that have been found here include four towers that remain standing today, many ceramic objects, jewellery, coins, and a few acropoli and neocropoli.