In the few years after his retirement from public life and before he was sentenced to suicide, the Roman philosopher Seneca wrote the majority of his texts, which included over one hundred letters of wisdom (espistulae morales) sent to his friend Lucilius. These letters are considered the first appearance of literary letters in Roman prose.
The letters are philosophical essays written by a very wise and witty old man concluding his life, an autobiography of our spiritual world. The issues that interested Seneca are eternally relevant.