Would like to know how Lord Shiva got name as "PanchaMukhan" ,what are 5 names ? Any images of this PanchaMukhas?? Also when did he become five faced?
After the period of Brahmas 100 years become over, then Mahapralaya comes. After the Mahapralaya the Universe is in unmanifested state. There are no name and forms, even the space is not there, everything is enveloped by darkness alone. The state of Universe is like as described in Nãsadiya Sukta of RigVeda which I discuss here. After a long time a desire comes in the unmanifest to become many. So, he chooses to make his own form which is most auspicious, all knowing abd the best. And that form is of five headed three eyed Lord which is named as SadaShiva (ever auspicious).
Shiva Purana Rudra Samhita Shristi Khanda chapter 6 describes it:
यस्येत्थ संविकल्पं सञ्ज्ञासञ्ज्ञोक्तित: स्म वै।
कियता चैव कालेन द्वितीयेच्छाऽभवत्किल॥१४॥
Its names go on changing. After a long time a desire developed in him to get himself multiplied. Or in other words he thought that he was one and he should be multiplied into many form.
अमूर्तेन स्वमूर्तिश्च तेनाकल्पि स्वलीलया।
सर्वैश्वर्यगुणोपेता सर्वज्ञानमयी शुभा॥ १५॥
The said being, having no form of his own, created an auspicious image, during the course of his own sport, possessing all the virtues and fortunes, besides the power, qualities and knowledge.
सर्वगा सर्वरूपा च सर्वदृक्सर्वकारिणी।
सर्वैकवन्द्या सर्वाद्या सर्वदा सर्वसंस्कृतिः॥ १६॥
A form which could move everywhere, displays all the forms, could visualise everything, should be all powerful and respectable by all, should be the ancient most and which could make all the people civilized.
परिकल्येति ता मूर्तिमैश्वरी शुद्धरूपिणीम्।
अद्वितीयमनाद्यन्तं सर्वाभासं चिदात्मकम्।
अन्तर्दधे पराख्यं यद्ब्रह्म सर्वगमव्ययम्॥ १७॥
Then he created the auspicious image of Isvara, then the original being who was beyond comparison, eternal, beyond measure, form of consciousness, which illuminates everything, form of pure knowledge, all pervading, indestructible, and supreme Brahman, disappeared.
अमूर्ते यत्पराख्यं वै तस्य मूर्तिः सदाशिवः।
अर्वाचीना पराचीना ईश्वरं तं जगुर्बुधाः।। १८॥
The manifest form of formless being is Sadasiva who is presently called by the people of wisdom as Isvara.
शक्तिस्तदैकलेनापि स्वैरं विहरता तनुः।
स्वविग्रहात्स्वयं सृष्टा स्वशरीरानपायिनी।१९।।
The lonely Isvara produced from his own body an everlasting Sakti. This Sakti did not effect his original body in any way.
प्रधानं प्रकृर्तिं तां च मायां गुणवतीं पराम्।
The said Sakti is variously known as Pradhan-Prakrti, Maya, Gunavati, Para. She happens to be the creator of the Buddhi-tattva (cosmic intelligence) and is unblemished.
सा शक्तिरम्बिका प्रोक्ता प्रकृतिः सकलेश्वरी।
त्रिदेवजननी नित्या मूलकारणमित्युत॥ २१॥
The same Sakti is also called Ambika, Prakrti, besides being the mistress of the three worlds. She is the mother of the three gods. She is everlasting and the main cause of the creation.
परः पुमानीश्वरः स शिवः शम्भुरनीश्वरः।
शीर्ष मन्दाकिनीधारी भालचन्द्रस्त्रिलोचन:। २५॥
Thereafter the said Parama-Purusa Siva also known as Isvara, having no other lord over him, who holds the Mandakini over his head. He has three eyes and a crescent moon on his forehead. ;
पञ्चवक्त्रः प्रसन्नात्मा दशबाहुस्त्रिशूलधृक्।
कर्पूरगौरः सुसितो भस्मोद्धूलितविग्रहः॥२६॥
Siva (SadaShiva) is five faced, a pleasant soul, holder of a trident, having complexion as white as the camphor, keeps on applying holy ashes over the body.
Thus Lord SadaShiva is called five-faced because he choose that form when he first manifested from unmanifest. In this way he also got his name as PanchaMukham.