Who in France declared war on Austria and subsequently other countries during France's revolutionary period, and why did they do it?

Regarding the first time that France went to war with
Austria during the revolutionary period, this war with Austria was declared on April 20,
1792.  It was the Legislative Assembly which declared war on
Austria.

There were a number of reasons for this
declaration.  The revolutionaries hoped to spread their revolution.  In addition, they
hoped that going to war would ensure that domestic enemies would stop trying to bring
down the revolution.  They hoped the war would also bring the most revolutionary/radical
of their leaders into power.  Conversely, King Louis XVI and other monarchists thought
that the war might help them, especially if the revolutionaries lost.  They hoped that
Austria and other countries might help to restore the
monarchy.

The French Legislative Assembly declared war on
Austria for revolutionary reasons.  They wanted to spread the revolution and to protect
and strengthen it at home.