That's a great piece of writing with strong ideas and atmosphere! I've made some light corrections for clarity, grammar, and natural flow while keeping your voice and style. Here's the improved version: "A century ago, true magicians were alive. Not quirky old men or mad witches, but rather ordinary-looking people who appeared respectable.
However, they were deeply interested in mysterious theories and practices. Respected gentlemen gathered in their mansions to study strange things: ancient manuscripts, spells from forbidden books, medieval legends, and the memories of Masons. Of course, there were also conversations about alchemy and astrology.
The participants of these mysterious gatherings included Oscar Wilde, Aleister Crowley (a notorious occultist), William Butler Yeats, Arthur Machen, and others. At present, I’m reading The Great God Pan by Arthur Machen. The pagan and bizarre elements in the story caused outrage in society at the time." P.S. I read various literary genres and have a strong interest in the culture and customs of different countries. That’s why I invite you to my conversation lessons in Ukrainian or Russian!