In the Shaiva Agamas, we find a theology that is sublime, yet formidable and decidedly Shaivite. In the Puranas that lean toward Shiva, however, the theology is mild, makes concessions toward other systems, and is presented in a mythic format. The Shiva Purana, for example, has very few sections dealing purely with theology, yet the text is replete with myths. Certain important legends of the Shiva Purana are not only repeated in different books of the text, but the tales either gain or lose certain elements in different books. One example of such a legend is that of the Jyotirlingam. In the Vidyeshvara Samhita (Book I) of the Shiva Purana, the episode of Jyotirlingam is followed by a chapter dealing with theology. In this chapter, Brahmā and Vishnu are instructed on the nature of Shiva, Omkara (Pranava) and the Panchakshara, by Shiva Himself. Within this instruction, one finds a form of Shaivite theology that is generally consistent with the Shaiva Agamas, yet makes concessions for its Puranic framework (i.e. allows for the interpretation that Brahmā, Vishnu, Rudra, and Maheshvara are individual "Gods" in their own right with different functions, yet originate from and are ruled over by [Sada]Shiva Himself).
Brahmā and Viṣṇu said:
O Lord, please tell us the characteristic feature of the five-fold duties beginning with creation.
I shall tell you the great secret of the five-fold duties, out of compassion for you. 
O Brahmā and Viṣṇu, the permanent cycle of the five-fold duties consists of creation, maintenance, annihilation, concealment and blessing. 
Sarga is the creation of the world; stithi is its maintenance; samhāra is the annihilation; tirobhāva is the removal and concealment. Anugraha is blessing. These five are My activities carried on by others silently as in the case of the statue at the portal. [3-4]
The first four activities concern the evolution of the world and the fifth one is the cause of salvation (mokṣa). All these constitute My prerogatives. 
These activities are observed in the five elements – sarga in the earth, stithi in the waters, samhāra in the fire, tirobhāva in the wind, and anugraha in the firmament (ākāśa or space). Everything is created by the earth, everything flourishes by virtue of the waters, everything is urged by the fire, everything is removed by the wind, and everything is blessed by the firmament (ākāśa). Thus intelligent men must know the same. [6-8]
In order to look after the five-fold activities I have five faces, four in the four quarters and the fifth in the middle. 
O sons, in view of your austerities, you two have received the first two activities: creation and maintenance. You have gratified Me and are blessed therefore. 
Similarly, the other two activities [annihilation and concealment] have been assigned to Rudra and Maheśa. The fifth one of Anugraha cannot be taken up by any other. 
All this previous arrangement has been forgotten by both of you due to lapse of time, not so by Rudra and Maheśa. 
I have assigned them My equality in form, dress, activity, vehicle, seat, weapons, etc. 
O dear sons, your delusion was the result of your not meditating upon Me. If You had realized My knowledge you would not have imbibed this false pride of being Maheśa yourselves. 
Hence, hereafter, both of you shall start reciting the mantra oṁkāra to acquire knowledge of Me. It shall quell your false pride as well. 
It is I who taught this great and auspicious mantra. Oṁkāra has come out of My mouth. Originally it indicated Me. 
It is the indicator and I am the indicated. This mantra is identical to Me. The repetition of this mantra is verily My repeated remembrance.
The syllable ‘A’ came from My northern face; the syllable ‘U’ came from the western; the syllable ‘M’ from the southern, and the Bindu from the eastern face. The Nada came from the middle face. Thus the complete set cropped up in five-fold form. Then all of them united in the syllable Aum. [18-19]
The two sets of created beings – Nāma [name] and Rūpa [form] are pervaded by this mantra. It indicates Śiva and Śakti. 
From this also is born the five-fold mantra [Namaśśivaya]. It indicates all knowledge. The syllables Na, etc. follow the order of the syllables A, etc. 
From the five-syllable mantra the five mothers [mantras] were born. The śiromantra is born of that. The three-footed Gāyatri also came out of the four faces. 
The entire set of Vedas and crores of mantras were born of that. Different things are achieved through different mantras but everything is achieved through oṁkāra alone.
All royal mantras are auspicious and directly accord enjoyment, but by this root-mantra enjoyment as well as liberation is achieved. 
The Lord in the company of his consort Ambikā assumed the role of Preceptor (Guru) for both of them. He screened them and placed His lotus-like hand on their heads as they faced north and slowly taught them the great mantra. 
The two disciples received the mantra by repeating it thrice, along with the requisite yantra and tantra duly expounded. By way of fees, the disciples dedicated themselves. Thereafter standing near Him with hands clasped in reverence addressed the Lord, the Preceptor of the universe. 
Brahmā and Viṣṇu said:
Obeisance to Thee of bodiless form.
Obeisance to Thee of formless luster.
Obeisance to Thee, the Lord of everything.
Obeisance to Thee, the Soul of everything.
Obeisance to Thee stated by the Praṇava (Aum).
Obeisance to Thee having Praṇava as Thy symbol.
Obeisance to Thee the Author of creation, etc. (five acts).
Obeisance to Thee of five-faces.
Obeisance to Thee identical with Pancabrahma forms.
Obeisance to Thee of five-fold functions.
Obeisance to Thee the Ātman , the Brahman, of endless attributes and power.
Obeisance to Śiva, the Preceptor, possessed of both embodied and bodiless forms.
After eulogizing the Preceptor in verses Brahmā and Viṣṇu bowed to Him. [28-31]
Śiva Purāṇa, Vidyeśvara Samhitā [Book I]:Chapter X:1-31
The Śiva Purāṇa (Part I). Trans. and annotated by a board of scholars.
Aum Namah Śivāya.