The relationship between the Giants and their tenant crumbled after the 1920 season when Yankee attendance boosted by their new slugging sensation doubled to 1,289,422. That was over 100,000 more than the Giants, who, in 1921, notified the Yankees to vacate the Polo Grounds as soon as possible. With their departure from the Polo Grounds now inevitable, Yankee co-owners Jacob Ruppert and Tillinghast l'Hommedieu Huston set out to build a spectacular ballpark of their own, Baseball's first triple-decked structure. With an advertised capacity of 70,000, it would also be the first to be labeled a "stadium."