Hardcore Gaming 101 has followed up its timeline for 2D fighting games with another comprehensive chronicle of key events and releases for a specific genre: action roleplaying games from the United States and Europe (online titles not included, as far as I could tell).

The "Brief History of Western Action RPGs" starts with Adventure in 1978 and ends with 2010 titles like Mass Effect 2 and Fallout: New Vegas, covering other critical in-between releases like the Ultima and Quest For Glory series.

All of the entries have short notes on their significance, too, like this entry on adventure game Knight Lore:

"[It] explores the isometric perspective (and later influences the use of the perspective in Adventures/RPGs in general, as well as Solstice and its successors in particular, which in turn inspires Landstalker and its sequels)."
You can pore through the entire thing here.