Did "soshite" develop from an overused "te"-form?

Question

I'm helping out as a tutor for Japanese in my university and a student asked me, if "soshite" may be derived from a verb in "-te" form.

Now, I know that there are a lot of similar-sounding words in the Japanese languages, but since the "-te" form is used to connect two sentences and so is "soshite" it got me thinking.

Maybe there's anyone out there with helpful insight :)

Answer 1

Yes!

From 大辞林

そして

[0] (接続)
→ そうしてに同じ。

そうして

さう— [0] 【然うして】
(接続)

1. 前に述べた事柄を受けて、それに引き続いて起こる事柄を述べる。それから。「あたりが暗くなった。—大粒の雨が降り始めた」
2. 全件に述べた事柄に後件をつけ加える。その上。さらに。「文学・歴史—教育と幅広く活躍する」

そうして is from そう and して (te-form of する). Here そう points not to something pertaining to the listener ("you"), but to the content of the previous (words or) sentence(s).

Of course そう belongs to こう・そう・ああ・どう. こうして and ああして also exist, but どうして "why" (or "how come") is probably the next most common of these after そ(う)して.