Analysis of information sources in references of the Wikipedia article "Judges 1" in English language version.
Judges 1: 18-19 may be an indication, especially if the Septuagint version of Judges 1:18 is taken as superior to the Masoretic text, i.e., that the Israelites were unable to take the valleys and towns, specifically Gaza, Ashkelon, and Ekron, because the Canaanites had chariots of iron.