Wonder What They'd Think of the Cell Phone

Regulations governing attendance at the Vienna Opera in 1897:

1. A canon (sic?) will be fired in the Imperial & Royal Arsenal at 5 p.m. daily as a signal to visitors to the Court Opera, that they should begin their preparations at home. On days when the performances commence at 6:30 p.m. the signal will be given at 4.30.
2. At 6 p.m. or 5.30, respectively, a second shot will give warning to ticket-holders who asre resident in the outer suburbs that their journey to the Court opera should now start. It has been arranged with Viennese householders that the concierges shall inform such tenasnts as intend to visit the Opera on that day as soon as the 6 p.m./ or 5.30 p.m. shot has been fired, and shall urge the such tenants to leave the house immediately.
3. As the tramway and omnibus system, particularly during the current pipe-laying operations, is exceptionally prone to involvement in traffic blocks and thus may cause ticket-holders in vast numbers to arrive late, all owners of season-tickets and ticket holders are obliged on their word of honour never to board one of the said vehicles to travel to the Opera once the above mentioned signal has sounded.

—Ruth Bereson, The Operatic State (2002)

As retrieved from Google books (link).