In 1945, Haldor Topsøe raised concerns in Ingeniøren (The Engineer, a Danish engineering and technology publication) and referred to it as »a bleak chapter« in the history of engineering leadership. This marked the beginning of a revolution that, 30 years later, manifested itself as DIEU – and today lives on as Mannaz. Mannaz, an international training and consultancy company owned by IDA, has, throughout the years, contributed to transforming engineers into competent leaders. In 2025, the company celebrates its 50th anniversary. We spoke with CEO Marianne Egelund Siig about the journey from spreadsheet-based further education to leadership programmes shaped by empathy, sustainability, and human insight.