It was in Christmas 1923 that Maury must have discovered Karl Barth, thanks to a little volume of sermons of Barth and Thurneysen (Come Holy Spirit), which Rene Guisan presented to him on that occasion. According to the testimony of his family, Maury never failed to remind them of the debt of gratitude that he owed to Guisan. A little time afterwards in 1924 Maury settled with his family in Ferney-Voltaire, still in French territory but not far from Geneva, to take up a pastorate in the Reformed parish. So his discovery of Barth just about coincided with his arrival in the region of Geneva.
At about the same time, in October 1924, the Dutchman Willem-Adolph Visser’t Hooft, future general secretary of the World Council of Churches, also settled in Geneva, serving on the International Committee of the YMCA. Being of Arminian background (therefore liberal), Visser’t Hooft, had also just discovered Barth a little before Maury, in 1922 . Maury and he had already met at an international Christian student conference in England. Visser’t Hooft had begun to regularly attend worship services held by Maury, and the two men quickly became friends, speaking of all that Barth’s theology could mean for them. Besides, their intimacy only increased when in 1931 Maury became secretary of the International World Student Christian Federation in Geneva with Visser’t Hooft at his side. “For three years they shared the same office”, Suzanne de Dietrich  said. “This partnership between an expansive Southern Frenchman and a reserved tenacious Dutchman must have been very amusing at times”. So as he became more deeply familiar through his discussions with Visser’t Hooft, Maury wanted to make Barth more widely known in French, particularly through the journal Foi et Vie of which he had become the editor in 1928. So he began to publish articles which introduced Barth’s theology ; he especially wanted to put in front of French speakers Barth’s actual texts, translated into their language.
And so it was that Maury began a correspondence with Karl Barth by a letter sent on 4 December 1928 . He asked for permission to translate several texts of Barth’s in Foi et Vie. Barth’s response dated 9 December written in French  was prudent: he was concerned that the translator should be “in general a good theologian and someone who knew my theology especially well ”; more than that he expressed the wish to be able to look at the translation before it was published. Altogether, these first letters had a tone of reserved polite formality, while already allowing for some cordiality. In the summer of 1931, Maury had already thought of the idea of visiting Barth in Bonn, along with Visser’t Hooft. Circumstances obliged them to put off this visit until the month of March 1932. Many years later, Barth himself still vividly remembered that time: “The two of them came to see me at my mother’s house in Bern where I was on holiday. It was of course Pierre who led the discussion. I can still see him before me and feel the fresh air that he brought with him ”.
From then on the ice had been broken; their letters abundantly bear witness. The reciprocal attraction must have quickly given place to an ever-growing friendship, especially from the moment where they stopped using the more formal ‘vous’ and adopted the intimate ‘tu’, when Barth went to Paris in April 1934. “We understood each other so well”, as Barth recalled in his article in 1956 for Reforme. “We were so naturally in agreement on all the great and important things, and yet also so sharply in disagreement on secondary questions, that our coming together could never have become unfruitful or boring. We never wondered what to talk about as we were always so eager to exchange our ideas”.
 He confirmed in a letter of 1/9/1980 that he had not met him personally until 1926 in Holland.
 Fifty Years of History- the International Federation of the Student Christian Movement (1895-1945), Paris, 1945, p. 93.
 This is, in particular, the origin of the two texts of Visser’t Hooft “The Message of Karl Barth” (Faith and Life 1928, pp 915-21) and “Introduction to the Theology of Karl Barth” (ETR? 1931, pp 3-23), but also in other ‘Barthian’ texts of Visser’t Hooft which were published at the same time either in Foi et Vie (Faith and Life) of Le Semeur (The Sower) and had a foothold in the ETR, the journal of the Faculty of Montpellier, through the intermediary of his father who was a Professor there.
 So had Barth already heard about Maury? Nothing in their correspondence allows us to think so. Still it is possible that Visser’t Hooft mentioned the name of his friend on the occasion of his first visit with Karl Barth in 1926. ……
 Not all Barth’s letters were written in French. This one is remarkable for the quality of its French: Barth must have had the help of a translator for this letter. When, later he wrote directly in French to Maury, his syntax was not nearly so precise.
 Letter from Barth to Maury 11/6/1931.
 Reforme, 18.2.1956. …Barth mentions this visit in a letter to Thurneysen 24/3/1932.
Taken from Reymond, B. 1985. Theologian or Prophet, French speakers and Karl Barth before 1945, Symbolon, L’Age d’Homme, Lausanne, pp 53-54. Translated by Simon Hattrell.