Complex sentence: Each Summer Tirpitz would go to St Blasien with his aids to work on naval plans, then in September he would travel to the Kaiser's retreat at Romintern, where Tirpitz found he would be more relaxed and willing to listen to a well argued explanation.
Split into simpler sentences: Each Summer Tirpitz would go to St Blasien with his aids to work on naval plans. Then in September he would travel to the Kaiser's retreat at Romintern, where Tirpitz found he would be more relaxed and willing to listen to a well argued explanation.