CAIRO — For over a thousand years, Cairo’s oldest mosques kept their doors open — through the Black Death of the 14th century, the devastating cholera epidemics of the 19th century and the Spanish flu in the winter of 1918 that claimed 140,000 Egyptian lives.

Then the coronavirus hit.

On the first day of the lockdown at Al Azhar, a famed center of scholarship that opened in A.D. 972, tears flowed down the cheeks of the muezzin, Sheikh Mohamed Rashad Zaghloul, as he made the call to prayer in an empty hall.

“It was hard on my heart,” he said after midday prayers one day last week at the mosque, where a stray cat meandered between the ancient pillars. “When I call people, nobody can come. It feels like God is refusing us.”

The shuttered ancient mosques are a harbinger of another event that will be jarringly altered by the pandemic. Ramadan, the holy month of fasting, begins at the end of this week and promises this year to be the strangest experienced by any Cairene, not to mention 1.8 billion Muslims worldwide.