His noble soul showed itself also in his friendship for many of his contemporaries; "there is nothing sweeter nor lovelier than mutual intercourse with friends", he used to say. His most intimate friend was Joachim Camerarius, whom he called the half of his soul. His extensive correspondence was for him not only a duty, but a need and an enjoyment. His letters form a valuable commentary on his whole life, as he spoke out his mind in them more unreservedly than he was wont to do in public life. A peculiar example of his sacrificing friendship is furnished by the fact that he wrote speeches and scientific treatises for others, permitting them to use their own signature. But in the kindness of his heart he was said to be ready to serve and assist not only his friends, but everybody. His whole nature adapted him especially to the intercourse with scholars and men of higher rank, while it was more difficult for him to deal with the people of lower station. He never allowed himself or others to exceed the bounds of nobility, honesty, and decency. He was very sincere in the judgment of his own person, acknowledging his faults even to opponents like Flacius, and was open to the criticism even of such as stood far below him. In his public career he sought not honour or fame, but earnestly endeavoured to serve the church and the cause of truth. His humility and modesty had their root in his personal piety. He laid great stress upon prayer, daily meditation on the Bible, and attendance of public service.