Around 841, the Republic of Venice sent a fleet of 60 galleys (each carrying 200 men) to assist the Byzantines in driving the Arabs from Crotone, but it failed. During this campaign Al-Mu'tasim discovered that some of his top generals were plotting against him. Many of these leading commanders were arrested and some executed before he arrived home. Al-Afshin seems not to have been involved in this, but he was detected in other intrigues and died in prison in the spring of 841. Caliph al-Mu'tasim fell sick in October 841 and died on 5 January 842.