 In 1972 he published his first solo album, entitled "Da steh ich nun".Siebald gained an international following with his performances at Eurofest '75, the international youth conference and evangelistic crusade which was organized by the Billy Graham organisation in Brussels.Siebald has often been compared with the singer-songwriter Reinhard Mey for his style, and sometimes with Graham Kendrick for his influence on Christian music in his country.