(left) and
Willi Stoph, 1967 On 1 May 1945 Matern returned to Germany with
Anton Ackermann's group. He was one of the signatories of the
programmatic appeal of the Central Committee of the KPD of 11 June 1945. Until 1946 he was the first secretary of the district leadership of the KPD in Saxony. After the
unification of the SPD and KPD in the
Soviet zone of occupation, Matern served as chairman of the regional association of Greater Berlin of the Socialist Unity Party of Germany (SED) from 1946 to 1948, alongside . Matern was a member of the central secretariat of the party executive from 1946 to 1950, and was made chairman of the Central Party Control Commission (ZPKK) on 21 October 1948 and a member of the
Politburo of the Central Committee of the SED in 1950. In the Politburo, he was responsible for controlling the “Traffic Department” of the Central Committee, which was responsible for the secret connections to the KPD in West Germany, which was illegal from 1955, and later to the
DKP, and for the financing of these parties. As one of the leading politicians he participated in the
Marxist–Leninist orientation of the SED. From 1949 he was a member of the
Provisional People's Chamber, from 1950 to 1954 as vice-president, then as the first deputy of the president and from 1957 to 1960 as chairman of the standing committee for the local representations. He was a member of the
National Defense Council of the GDR. Following the
East German uprising of 1953, a majority of the Politburo supported removing
Walter Ulbricht as First Secretary of the party; only Matern and one other,
Erich Honecker, remained loyal to Ulbricht. Ulbricht was saved with the support of Soviet leader
Nikita Khrushchev, and subsequently purged the opposition from the Politburo. Matern became a member of the
International Federation Resistance of Fighters General Council in 1963. Matern was convinced of the SED's claim to leadership. At the 7th All-German Workers' Conference in Leipzig in 1958, he said:“To have state power in your hands is of great importance. [...] We never think of giving up workers' and peasants' power again. We will not allow anyone to run for election who wants to rebuild capitalism. [...] That is why there is no opposition based on bourgeois ideas. " == Death and legacy ==