How did the word Solicitor come to mean two different professions?

In the US, it’s very commonplace to see signs on homes and businesses indicated "No soliciting", which I construe to mean, "Please don’t show up just to try and sell us something. We’re not interested." I’ve had friends whom have worked as door-to-door salespeople and as canvassers, both of which would be considered solicitors and not welcome at those locations.

In my work, I occasionally have need to interact with municipalities and their designated attorney, whose position is often titled, "Township Solicitor." Presumably this person is also someone that you don’t want to show up at your door as well, but for very different reasons.

Given that these are two very different professions that evoke a very different image, I’m curious how they came to both use the same word.