The Houthis, a Yemeni political and military organisation, have made headlines across the World since they began blocking the Red Sea nearly six months ago. But despite their association with Gaza, and Iran's "Axis of Resistance", their origins in the turbulent Yemeni politics of the 1990s and 2000s are not widely understood.

This is the first half of a two-part conversation seeking to explain the Houthis' rise to prominence, and covers the unification of Yemen in 1990, the arrival of Sunni extremism in the country from Saudi Arabia, and the violent attempts of President Saleh to impose order on Yemen. All of these strands, and others, contributed to the Houthis' development, and sent Yemen hurtling towards the Arab Spring, and civil war.

My guest today is Isa Blumi. Isa is an associate professor of Turkish and Middle Eastern Studies at Stockholm University. Isa has published several books on Turkey, the Balkans, the late Ottoman Empire and Yemen, including Destroying Yemen: What Chaos in Arabia Tells Us about the World.