Their tracks were dark,
their trail very black,

The bird that floats in the air,
swoops less swiftly than their leader,

Drudgery was it for the fellow,
who taught all four of them their ways,

On their ceaseless visits,
to the vessel of gold.

An old russian legend tells abouth a fourth magi called Artaban or Coredan, he travels separately from the other three and never reaches Bethlehem.

I also always thought there where "Eight days a week".