Urza's block (also referred to as "Artifacts block", "Urza block", "Urza's Saga block", "Saga block") is the fourth block, consisting of the large expansion Urza's Saga () and the two small expansions Urza's Legacy () and Urza's Destiny (). The storyline cycle is officially known as the "Artifacts Cycle". The block came out in 1998–1999.
The Urza's Saga design team originally had concepted the block as an Enchantment block, but in order to capitalize on the Urza-story, the brand team dubbed the block The Artifact Cycle. In development R&D made a few mistakes on the block and was labeled "bah-roken" by Mark Rosewater. Some of those broken cards were artifacts, but interestingly none of them were enchantments. "So the enchantment theme kind of got buried. In fact, very few players even recognized it as an enchantment block."
In fact so many broken cards were in Urza's Saga that the following period became known as Combo Winter. Too many overpowered cards and combos filled the tournament. This moved the DCI to ban a large amount of cards in December 1998 and the CEO of Wizards of the Coast to threaten R&D that they would be fired if they would break the constructed environment again.
- Destroy: Based on Rain of Salt () from Urza's Saga, Urza's Legacy continued with Peace and Quiet () / Rack and Ruin () pair.
- Until end of turn: Based on Symbiosis () from Urza's Saga, Urza's Legacy continued with Hope and Glory() / Sick and Tired () pair.
- Jesse Klingensmith. "Urza's Block Booster Drafts and Memphis Grand Prix Trial", Wizards of the Coast.
- Aaron Forsythe (February 20, 2004). "Skeletons in R&D’s Closet. Developer's notes from Urza's Saga block". magicthegathering.com. Wizards of the Coast.
- Mark Rosewater (November 24, 2014). "Top 8 and a Half Tales". magicthegathering.com. Wizards of the Coast.
- Mark Rosewater (November 10, 2003). "Make No Mistake". magicthegathering.com. Wizards of the Coast.
- Mark Rosewater (October 16, 2012). "What was it like getting yelled at for Urza's Block?". Blogatog. Tumblr.
- Mark Rosewater (June 05, 2016). "Combo Winter WAS job-threatening, though, wasn't it?". Blogatog. Tumblr.
- Mark Rosewater (March 05, 2017). "Which was the block where the entire R&d team nearly got fired because it was so bad?". Blogatog. Tumblr.