History behind street names

Well lads, has anyone any resource that gives the history behind the street names in Limerick City?

I often do be walking around the place pondering about street names. Now I’m aware of the origins of some of them eg:

Henry Street (Edmund Henry Pery, first Earl of Limerick)

Wolfe Tone Street (Named after that sound republican lad)

But like Gerard Street. Who’s Gerard? What did he do to have a street named after him?

Or why is Denmark street called Denmark street?

Why is there an area called Pennywell?

Any interesting street naming facts also welcome.