Irving Berlin's 200-odd songs written between 1907, the date of the first one, and late 1914, when his first complete show for the musical stage (Watch Your Step) opened at New York's Globe Theatre, are virtually identical to one another in their published piano/vocal format. Like other Tin Pan Alley songs of the early twentieth century, most of them consist of a brief piano introduction, a few bars of vamp, then several verses, each followed by a chorus. All are in major keys and most have a tempo marking of moderato. Piano introductions are drawn from either the first or last phrase of the chorus, the vamp anticipates the melodic beginning of the verse, and both verse and chorus are usually made up of four 4-bar phrases in C or four 8-bar phrases in other metres.