Was baptism always by immersion?

[tonychanyt]

The book of Didache was written in the first century AD. Didache:

And concerning baptism, baptize this way: Having first said all these things, baptize into the name of the Father, and of the Son, and of the Holy Spirit, in living water. But if you have no living water, baptize into other water; and if you cannot do so in cold water, do so in warm. But if you have neither, pour out water three times upon the head into the name of Father and Son and Holy Spirit.

Didache was being pragmatic, offering different modes of baptism. The preference was full immersion in a body of running water.