Petros Kokkalis  Petros Kokkalis (Greek: Πέτρος Κόκκαλης, 1896 - 1962) was a Greek medical doctor, academic and politician, member of the Communist Party of Greece, and Minister in the (internationally unrecognized) Provisional Democratic Government during the Greek Civil War. He was the personal physician to East German leader Walter Ulbricht and is the father of the billionaire businessman Sokratis Kokkalis, one of the wealthiest and most influential people in Greece. He was born in Livadeia, Greece, in 1896, to a prosperous family. He first studied medicine at Athens University and received a PhD from the University of Bern in Switzerland. During the Nazi Occupation of Greece he joined the left-wing National Liberation Front (EAM), and became a Minister in EAM's government that controlled the liberated areas of Greece, under guerrilla control, the Political Committee of National Liberation (PEEA). Later, in the Greek Civil War, he was a minister in the internationally unrecognized Provisional Democratic Government. After the defeat of the communists, he fled to East Germany, where he continued his academic career. He died in East Berlin in 1962, aged 66, after suffering a myocardial infarction.