In the old time of Greece, they had an army, just like how we have soldiers today. But in that army, some of the soldiers loved people who have the same gender as them. This is what we call homosexuality.
The people who were attracted to the same gender were called "erastes" if they were older, and "eromenos" if they were younger. They were called these names because erastes means "lover," and the eromenos means "beloved."
Their love was seen as something special and sacred in the ancient Greek army. It was believed that this love made the soldiers closer and more willing to fight for each other. They believed that this love can make men stronger and more successful in war.
Sometimes, the older soldiers would take care of and protect younger, newer soldiers, which made them closer to each other. These relationships were allowed and recognized by their society, and they thought it was a normal and natural part of life.
So, in summary, some soldiers in ancient Greece loved people who have the same gender as them, and their relationships were supported by their society and believed to make them stronger and closer to each other in the army.