Sergius and Bacchus (Kutchuk Aya Sofia) and St Sophia are erections of Justinian the Great.
==Mesopotamia== Altars are found from the earliest times in the remains of Babylonian cities; the oldest are square erections of sun-dried bricks.
Of modern erections, the concert hall, the law courts and a memorial fountain to the cartographer Gerhard Kremer (Mercator) are worthy of mention.
Of the recent erections, the polytechnic, the exchange, the monument of the German writer, Johann Gottfried von Herder, who lived at Riga towards the end of the 18th century, the gymnasiums (schools) of Lomonosov and Alexander I.
Of modern erections the new cathedral (Dom), on the Spree, which replaces the old building pulled down in 1893, stands first.