What other older resources can be used to learn math? The basic of basics, starting points in history that are often overlooked
In general we're better off reading modern treatments because they have more context and more convenient notation.
That said, it's important to read the old texts precisely because they elucidate the state of the art as it was, and so help us understand not only how far we've come but how we got to where we are now.
One of my professors wrote the canonical biography of Boole. I read it, and learned as much about Boole as I did about Des MacHale.
In a roundabout way what I'm trying to say is learn the mathematics and the mathematician, you won't be disappointed.