In Japan, even more than 2 century ago, more than 50% general people could read and write the language. When the kids enter to school, they study kana syllabary first.
Before modern era, Edo period, Japanese people didn't use current systematic table of the Japanese kana syllabary. We have used different kana syllabary order as a poem.

It is called as「いろは歌(Iroha uta)」. There are 47 of kana in Japanese language. Iroha-uta is using one of each kana only once. I can say it is very amazing works.
Iroha-uta had been used for 1000years for Japanese education. It is anonymous. But he must be Buddhist. Because the meaning of Iroha-uta is based on the Sutra of Buddhism.

I would like to introduce it for you.

いろはにほへと ちりぬるを
わかよたれそ  つねならむ
うゐのおくやま けふこえて
あさきゆめみし ゑひもせす(ん)

色は匂へど 散りぬるを
我が世誰そ 常ならむ
有為の奥山 今日越えて
浅き夢見じ 酔ひもせず

【Translated】(By Hekishusai)
The formed object is magnificent. But, it is on the destiny of ruin in some time.
The all things in nature of the world can't exist forever.
If you dedicate to the agony in the world of the relative view entirely,
you will get the realization without any vain illusion.

I'm sorry my rough translation. But I hope you can feel it a little.
It seems very deep meaning.

Today, we don't use this poem for hiragana study. But we still understand it.

SD110303 Hekishusai