Before the World War One. there were many secret alliances. but there were also reciprocated suspicions among some European powers during a few former decades (since 1876). These were alliances and suspicions involving their plans for geopolitical recomposition of the Balkans. https://www.kerrenneur.com/product-category/warming-equipmentother-commercial-warming-equipment-food-servicecommercial-kitchen-equipmentfood-holding/