Simon was aiding Guy, who had been injured by a crossbow bolt, at the Siege of Toulouse on 25 June 1218 when he was struck in the head by a stone from a mangonel and killed.
Simon membantu Guy, yang terluka oleh baut panah, di Pengepungan Toulouse pada tanggal 25 Juni 1218 ketika kepalanya dipukul oleh batu dari mangonel dan terbunuh.