I took a course in hymnology during my Master of Divinity program at Brite Divinity School around 1996, when the Hymn Society will still housed on campus. The textbooks were written by esteemed hymnologist and minister Erik Routley (1917-1982) with the lectures supplemented by recorded lectures by Routley, helpful because hymns need to be heard and sung, and he was prone to sing fragments.
I loved that class, but I hadn't heard the recordings again until a couple of days ago, when I discovered his Christian Hymnody series -- originally issued on tape -- playable online.
It covers the history of Christian hymnody though the end of the nineteenth century, and if you don't have a background in hymnology it'll probably help deeply. A bit of a caveat there, as I've not replayed it all: it runs about three hours.
Later notes: It runs in a conversational style,like having dinner with a very knowledgeable person who dominates the conversation. But don't expect to learn anything about the Eastern church. Or is it six hours? A tape has two sides, you know.