What is the earliest Christian use of a worship leader?

Music directors existed in Old Testament times ([see these 56 references](http://www.biblegateway.com/keyword/?search=director+of+music&searchtype=all&version1=102&language1=en&spanbegin=1&spanend=73&resultspp=500&displayas=long&sort=bookorder)) . But was there such a thing as what we now call a *worship leader* in *Christian* (New Testament and early church) times? Or is it a modern (re-)invention? Additional information: we know that [hymns were sung in Biblical times](http://www.biblegateway.com/keyword/?search=hymn&searchtype=all&version1=102&language1=en&spanbegin=1&spanend=73&resultspp=500&displayas=long&sort=bookorder) , including by Jesus and the disciples. And we know there were [gatherings of thousands](http://www.biblegateway.com/passage/?search=Acts%202:41&version=NIV1984) . These two facts suggest to me the early church may have worshiped in large groups, which would imply someone coordinating it. But I have no idea if that resembles a modern worship leader.