I am trying to write a paper on Elizabeth Browning's "Reward of service" . I was able to find the complete poem online but I cant seem to find anything else about it.

It goes "The sweetest lives are those to duty wed,, whose deeds both great and small, Are cloe-know strands of unbroken thread.... A poor man served by thee shall make thee rich...."

Does anyone know 1) If it is part of a book or collection?, 2)When she wrote it? what stage in her life (young old, anything)? 3)What context if any.

Actually, anything you can tell me about it would be a big help Its been driving me nuts for a week now