[3] After university, Magenis entered the diplomatic service and in August 1825 became an attaché to the British Legation at Berlin.
[7][8] In January, 1837, Magenis was invited by Alexander Pushkin who met him at a ball in Countess Maria Razumovskaya's house in Saint Petersburg, to be his second before his fatal duel with Georges d'Anthès.
[15][7] In 1837, the esteemed Russian poet Alexander Pushkin asked Magenis, then attaché to the British Consulate-General in Saint Petersburg, to be his second at his doomed duel with his brother-in-law Baron d'Anthès van Heeckeren, a member of Russia's Imperial Knight Guards.
Pushkin had faced scandalous rumours that his beautiful young wife, Natalia, was having an affair with d'Anthès de Heeckeren, who had recently married her sister.
Not finding you, I supposed that you had left, and as a visit at this hour could awaken the suspicions of Madame your wife, I prefer to address these lines to you.
I told Mons-r d'Archiac that you had spoken to me of your affair with Monsieur de Heeckeren, engaging me to act as your second—and that without taking on this role definitively I had promised to speak to him.
However, I think I have understood that the affair cannot be settled peaceably, the hope of which might have tempted me to intervene; consequently I must beg you, Sir, not to request me to take on the role that you wished.
Nor do I believe that my refusal will cause you embarrassment.Thus on 8 February 837, the duel went ahead at Saint Petersburg's Black River, where Pushkin was fatally injured and died two days later.