---
title: "A small format. A lasting idea."
description: "Meet Markdown: readable text that can become a structured document."
canonical: https://editmd.app/learn/lessons/origins/
markdown: https://editmd.app/learn/lessons/origins.md
status: pre-release, waiting list open
generated: editmd-website
---

# A small format. A lasting idea.

Lesson 01 of 12 in Markdown School. Meet Markdown: readable text that can become a structured document.

## Before the preview, there was plain text

Open a Markdown file in a text editor and you see the words together with a few simple marks. `#` can introduce a heading. Asterisks can mark emphasis. A renderer interprets those marks and displays a structured document. The `.md` extension is a filename convention; you do not need a special app to read the text.

John Gruber introduced Markdown on **15 March 2004** to help people write for the web using readable plain text that converts to HTML. His original announcement describes a text-to-HTML tool and publishing integrations. [Read the original announcement](https://daringfireball.net/2004/03/introducing_markdown).

Aaron Swartz contributed ideas, design feedback and testing. Gruber also credits plain-text email as a major influence on the syntax. [Project description and acknowledgements](https://daringfireball.net/projects/markdown/).

## One file, two ways to read it

```markdown
# Garden notes

A little room to **grow**.
```

The source has a heading and a paragraph. The preview displays their meaning through typography. Font choice, colours and page layout belong to the renderer; they are not stored in those Markdown marks.

A Markdown file is useful for notes, project documentation and other structured writing. GitHub, for example, displays Markdown READMEs as an introduction to a repository. [GitHub’s README guide](https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-readmes).

## Why it appears in AI workflows

Modern tools also read Markdown as context and instructions. That is a newer application of readable text, not Markdown’s original purpose. A heading helps organize your request; it does not prove the content is correct. We will practise a bounded review in [the AI lesson](/learn/lessons/review/).

## Try it, then explain it

Change the source below. Afterwards, explain which characters belong to the title itself and which characters tell the renderer that it is a heading. You should be able to read your note without relying on the preview.

## Exercise

Write a # title for a note, leave a blank line, then add a short paragraph. Try changing the title and watch the result.

## Takeaway

The .md file is ordinary text. A renderer gives its marks a visual form.

Related guide: https://editmd.app/docs/markdown/. All lessons: https://editmd.app/learn.md