St. Scholastica was the sister of St. Benedict. St. Benedict had started a monastery, and she had started a convent. Once a year the two of them would meet and talk. Men were  not allowed inside St. Scholastica's convent, and likewise no woman could enter St. Benedict's monastery, so the two of them would meet in a small farmhouse somewhere between their two orders to talk.

One day she came to the house too talk with St. Benedict, who came with some of his monks, and the two of them spent the time praying together and discussing various things about the spiritual life. They ate dinner together, and eventually it grew late outside. 

St. Scholastica had a premonition that this would be the last year she met with her brother to speak together in the farmhouse, and so asked him, "Please, don’t leave me tonight. Let’s go on until morning. I want to speak with you about the wonderful things in the spiritual life."

"Sister," He replied, "What are you talking about? I can’t stay outside this late." If Benedict stayed outside his monastery for a whole night he would be breaking his own Rule.  

When she heard her brother refuse her request, St. Scholastica joined her hands on the table, laid her head on them, and began to pray. After a little while she raised her head, her prayer finished.

Outside, out of nowhere, lightning flashed, thunder shook the house as if it was an earthquake, and rain gushed from the sky in buckets, practically turning the road into a small stream. St. Benedict and his brothers couldn't so much as step out of the doorway because of the storm. 

"God forgive you, sister! What have you done?" St. Benedict demanded of the nun.

"Well," she answered meekly, "I asked you for a favor and you would not listen; so I asked a favor from God and He granted it. So, go away, if you can. Leave me and return to your monastery." 

St. Benedict was reluctant to stay, but did so against his will. He could hardly do otherwise, with the storm raging outside. The two of them were so engrossed in discussion about the spiritual life that they stayed awake the entire night.

Three days later St. Benedict was in his cell, as usual. He happened to look out his window and saw his sister's soul leave her body in the form of a dove and fly up to the secret places of heaven.  

He rejoiced, knowing that she was full of joy, and thanked God profusely with songs and words alike. He sent his brothers to bring her body to the monastery and lay it in a tomb. It was the exact same tomb he had prepared for himself.

Their minds had always been united in God; their bodies shared the same grave.

Adapted from the Dialogues of St. Gregory the Great.